JPH1090968A - Color image forming equipment - Google Patents

Abstract

(57) [Summary] [Object] To provide a color image forming apparatus capable of reducing a user's waiting time until printing. In a color image forming apparatus configured to switch a plurality of detachable developing units supported by a developing unit rotation unit (supporting member) to develop a latent image on an image carrier, Contacts (first contact members) 21 and 22 on the developing device rotation unit 11;
Contacts (second contact members) 23 and 2 which are opposed to and come into contact with 22
4, identification means 48 unique to the plurality of developing devices 47,
An electrical connection line on the developing device rotation unit 11, one end of which is commonly connected to the identification means 48, and the other end of which is connected to the contacts 21 and 22;
A control circuit (control means) 30 for detecting the presence or absence of each of the plurality of developing devices 47 through the contacts 21 and 22 and the contacts 23 and 24 to vary the image forming operation is provided. According to the present invention, since the mounting state of the developing device 47 can be monitored at any time,
This eliminates the need for the conventional detection time of the mounting state of the developing device, and thus achieves the above object.

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 using a plurality of detachable developing devices, and more particularly, to a variable image forming operation by discriminating the state of attachment and detachment of a plurality of developing devices. Related to the control to be performed.

[0002]

2. Description of the Related Art In recent years, color printers have been used as various means of expression for users. In particular, color page printers have attracted attention because of their quietness, high-quality printing, and high-speed printing. Hereinafter, a color laser beam printer which is one of such color page printers will be described.

The color laser beam printer is characterized in that a first latent image is formed by scanning a light beam on a photoreceptor in a main scanning direction, and the first latent image is visualized as a toner image. After the development, the transfer step of transferring the toner image onto a carrier such as a transfer drum is referred to as a first step, and the second, third and fourth steps are subsequently performed to transfer the toner images of respective colors. The multi-color image is recorded by transferring the image on the recording medium at a predetermined timing and then performing re-transfer collectively on recording paper as a recording medium at a predetermined timing.

FIG. 9 shows a cross section of a color laser beam printer. In FIG. 9, A is a mechanism of the color laser beam printer. 1 is a photosensitive drum, 4 and 4A are chargers, 5 is a semiconductor laser, 6 is a scanner motor, 7 is a polygon mirror rotated and driven by the scanner motor 6,
8 is a lens, 9 is a mirror, 10 is a cleaner, 12 is a separation claw, 13 is a fixing device, and 19 is a paper discharge tray.

An image signal S110 is output from the semiconductor laser 5.
A light beam L on / off modulated by a VDO signal (hereinafter, referred to as a VDO signal) is output. The light beam L emitted from the semiconductor laser 5 is scanned by a polygon mirror 7 and then moved through a lens 8 and a mirror 9. Through the photosensitive drum 1.

Reference numeral 14 denotes a paper feed roller 15, a paper feed cassette, and 16 a transfer drum. The transfer drum 16 comprises an insulating film 17 and an aluminum drum 18. Reference numeral 11 denotes a developing unit rotation unit, in which four color developing units 47M, 47C, 47Y, and 47Bk are supported. Each developing unit 47M, 47C, 47Y, 47Bk
Is provided with identification means 48 (see FIG. 11), which will be described later.
The loading positions of 7C, 47Y, and 47Bk are regulated. For example, the magenta developing device 47M is prevented from being loaded in the cyan developing device 47C.

The magenta developing device 47M is a first developing device that develops the latent image in the first process to form a magenta toner image as a first toner image, and the cyan developing device 47C is a second developing device. The second developing device develops the latent image at the time to form a cyan toner image as a second toner image, and the yellow developing device 47Y develops the latent image at the third process to produce the third toner image. A third developing device for forming a yellow toner image as an image, and a black developing device 47Bk for developing the latent image in the fourth step to form a fourth toner image for forming a black toner image. It is a developing device.

Reference numeral 20 denotes a shielding plate indicating the reference position of the developing unit rotation unit 11. The shielding plate 20 changes the output signal of the photosensor 2 when the developing unit rotation unit 11 is at a predetermined position. The output signal is a control circuit 3 described later.
0 (see FIG. 10).

Next, the operation of the color laser beam printer will be described.

First, the photosensitive drum 1 is charged to a predetermined polarity and a predetermined voltage by the charger 4, and the VDO signal S1
The photosensitive drum 1 is scanned and exposed by the light beam L modulated by 10 to form a first electrostatic latent image on the photosensitive drum 1. Next, the first electrostatic latent image is developed by the developing device 47M, and a magenta first toner image is formed on the photosensitive drum 1.

On the other hand, immediately before the recording paper P is fed at a predetermined timing and its leading end reaches the transfer start position, a predetermined transfer bias voltage having a polarity opposite to that of the toner is applied to the transfer drum 16.
And the first toner image is transferred onto the insulating film 17 on the transfer drum 16.

Next, after a second electrostatic latent image is formed on the photosensitive drum 1 by the light beam L, the developing device rotating unit 11
Rotates 90 degrees with respect to the developing device 47M and faces the photosensitive drum 1 in a non-contact state, and the second electrostatic latent image is developed by the developing device 47C to form a second cyan toner image on the photosensitive drum 1. It is formed. Then, the second toner image is transferred so as to overlap the position of the first toner image transferred to the insulating film 17 on the transfer drum 16.

Similarly, third and fourth electrostatic latent images are formed on the photosensitive drum 1, and the developing unit rotation units 11 are rotated by 90 degrees to face the photosensitive drum 1 in a non-contact state. The third and fourth electrostatic latent images are developed by the remaining developing units 47Y and 47Bk, respectively, and yellow and black toner images are transferred onto the insulating film 17 on the transfer drum 16 at a predetermined timing. The recording paper P is fed, and the four color toner images on the insulating film 17 on the transfer drum 16 are collectively transferred onto the recording paper P to form four color toner images on the recording paper P.

FIG. 10 is a perspective view showing the configuration of a control system of the developing unit rotation unit 11 shown in FIG. 9. In this figure, the same elements as those shown in FIG.
Hereinafter, the description thereof will be omitted.

When the developing unit rotation unit 11 rotates,
Contact 2 for each developing unit 47M, 47C, 47Y, 47Bk
1M, 21C, 21Y, and 21Bk (hereinafter, simply referred to as 21 when representing one of these four contacts) and 22M, 22C, 22Y, 22Bk (when representing one of these four contacts, , Simply referred to as 22) are located on the same locus, and the contact 21
A contact 23 is provided outside the developing device rotating unit 11 in opposition to the contact, and a contact 24 is provided outside the developing device rotating unit 11 in opposition to the contact 22.
Are arranged so as to contact each other at a predetermined position.

FIG. 10 shows that the developing device 47C reaches the developing position,
The contact 21C and the contact 23 are in contact with each other, and the contact 22C and the contact 24 are in contact at the same time. At this time, the control circuit 30 connected to the contacts 23 and 24 detects the presence or absence of conduction between the two contacts 23 and 24, detects the presence or absence of the developing device 24C, and performs a predetermined control operation to a mechanism (not shown). Do it for

FIG. 11 shows the developing device 4 when it reaches the developing position.
FIG. 7 is a cross-sectional view illustrating a state of a developing unit and a developing unit rotation unit. However, in FIG. 11, functional members such as a developing sleeve that functions in the developing process are not shown.

In FIG. 11, reference numeral 40 denotes a support member outside the developing unit rotation unit 11 for supporting the contacts 23 and 24 together with an insulating material 41C.

On the other hand, the developing unit rotation unit 11
The contact 21 and the contact 31 that are connected to the contact 24 and the contact 22 and the contact 32 that are connected to the contact 24 are connected to the insulating material 4.
It is supported together with 1A and 41B.

In FIG. 11, reference numeral 47 denotes a developing device. The developing device 47 includes a contact 33 that contacts the contact 31, a contact 34 that contacts the contact 32, and a connection line 35 that connects the contact 33 to the contact 34. Have.

As is apparent from FIG. 11, the connection line S1 and the connection line S2 are short-circuited by the connection line 35 only when the developing device 47 reaches the developing position. Rotating unit 1
1, the presence or absence of the individual developing device 47 is detected.

In FIG. 11, reference numeral 48 denotes identification means having a different shape for each developing device 47.
The developing device rotation unit 11 is configured to be rotatable only when the proper developing device 47 is inserted into the proper loading position. As a result, the loading positions of the respective color developing devices 47M, 47C, 47Y, and 47Bk in the developing device rotation unit 11 are regulated so that, for example, the magenta developing device 47M cannot be loaded at the position of the cyan developing device 47C.

FIG. 12 shows the developing unit rotation unit 1 shown in FIG.
1 is an equivalent circuit diagram. In this figure, the same elements as those shown in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted below.

FIG. 12 shows a state in which the yellow developing unit 47Y is connected to the control circuit 30. At this time, it is determined that the developing device 47Y is loaded by the determining function of the presence or absence of the developing device included in the second control circuit 80. Further, the second control circuit 80 has a function of stopping the developing device rotation unit 11 at the position shown in FIG. 12 based on the detection signal from the photosensor 2.

FIG. 13 is a timing chart showing the operation state of the second control circuit 80.

In FIG. 13, t1 indicates the time from when the power is turned on or the door is opened to when printing is completed, and t2 indicates the time during which the developing unit rotation unit 11 is operating.

Further, T1 is used to detect the presence / absence of the developing unit 47 while stopping the developing unit 47 (47M, 47C, 47Y, 47Bk) at the above-mentioned predetermined position in order to detect the presence / absence of the loading of the developing unit. T2 is a period during which the image forming apparatus can perform printing, T3 is a period during which the developing unit rotation unit 11 is operating for image formation, and T4 is a period during which power is turned on or the door is opened and the photosensitive drum 1 and the like are attached and detached. The sum of the period for detecting that the replaceable consumable item is in use and the period T1 are shown.

In the developing device detection period T1, the developing device 47
Are loaded, the standby state shown in the period T2 is entered, and the apparatus enters a print signal input waiting state. If at least one of the developing devices 47 is not loaded, the user is notified by a display device (not shown) that the undeveloped developing device 47 is loaded.

[0029]

In the conventional color laser beam printer described above, as shown in FIG. 13, it takes at least T4 from power-on or door opening to the start of printing. Among the T4s, the control time T1 for detecting the presence or absence of the developing device 47 by rotating the developing device rotation unit 11 is the longest, and there is a problem that the user's waiting time until the end of printing is long.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a color image forming apparatus capable of reducing a user's waiting time until printing.

[0031]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a developing method of developing a latent image on an image carrier by switching a plurality of detachable developing devices supported by a supporting member. In the configured color image forming apparatus, a first contact member on the support member, a second contact member outside the support member in contact with and in contact with the first contact member, and the plurality of developing devices. A unique identification means and an electrical connection line on the support member, one end of which is commonly connected to the identification means, and the other end of which is connected to the first contact member; Control means for detecting the presence or absence of each of the plurality of developing devices via the first contact member and the second contact member to vary the image forming operation is provided.

Therefore, according to the present invention, the mounting state of the developing device can be monitored at any time, so that the time for detecting the mounting state of the developing device is not required as in the prior art, and the waiting time until printing by the user is reduced. Is done.

[0033]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> FIG. 1 is a perspective view showing the structure of a developing unit rotation unit in a color image forming apparatus according to the present invention. In FIG. 1, the same elements as those shown in FIG. In the following, description thereof will be omitted.

In FIG. 1, reference numeral 25 denotes each developing device 47 (47).
M, 47C, 47Y, and 47Bk), which are electrically connected to each other.
(21M, 21C, 21Y, 21Bk) and contact 22
(22M, 22C, 22Y, 22Bk)
A, 25B. The contact 21 and the contact 22 are respectively connected to the opposing contact 23 and the contact 24 by the connection line 2.
It is always connected via 5A and 25B. For this reason,
The control circuit 30 can check the connection state of the developing device 47 at any time.

FIG. 2 is a cross-sectional view of the developing unit 47 and the developing unit rotating unit 11 according to the present embodiment. In this figure, the same elements as those shown in FIG. The description of is omitted.

The difference from the conventional example shown in FIG.
The point is that the resistor 36 is connected between the contact 1 and the contact 21. Each of the resistors 36 is provided individually for each of the developing devices 47. The resistance value of each of the resistors 36 is different from each other, so that the control circuit 30 can detect whether or not each of the developing devices 47 is loaded. It is.

FIG. 3 shows the developing unit rotating unit 11 shown in FIG.
In this figure, the same elements as those shown in FIG. 12 are denoted by the same reference numerals, and a description thereof will be omitted below.

The difference from the conventional example shown in FIG. 12 is that resistors 36M, 36C, 36Y and 36Bk for recognizing the loading of each developing device 47 are connected to the connection lines 25A and 25B at the contact point 33 of each developing device 47. The point is that they are connected in parallel. Then, resistors 36M, 36C, 36Y, 36 are added to a voltage adder 50 composed of a resistor 37, an operational amplifier 39 and a resistor 38.
Since Bk is connected, the output voltage Vo of the voltage adder 50 differs depending on the loaded state of the developing device 47.

In particular, the resistance r1 of each of the resistors 37, 36C, 36Y and 36Bk is compared with the resistance r1 of the resistor 36M.
Assuming that f, r2, r3, and r4 are rf = r1 r2 = r1 * 2 r3 = r1 * 4 r4 = r1 * 8, as shown in FIG. 4, detection is performed for all the loaded states of the developing device 47. An output voltage Vo that can be easily obtained is obtained.
In FIG. 4, ○ indicates that a developing device is provided, and X indicates that no developing device is provided.

Thus, as shown in FIG.
Output voltage Vo is 1 if all are loaded in proper positions.
5 * V. For example, if the black developing device 47Bk is insufficiently loaded, the output voltage Vo becomes 14 * V, and the developing device 4
7 can be clearly identified. And
Reading of these output voltages Vo by the control circuit 51 is as follows.
It is possible at any time regardless of the rotation position of the developing unit rotation unit 11.

FIG. 5 is a timing chart showing an operation state of the control circuit 51 shown in FIG.
The same elements as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted below.

As shown in FIG. 5, in this embodiment, there is no operation period T1 (see FIG. 13) for detecting the presence or absence of the developing device by rotating the developing device rotating unit 11 shown in the conventional example. In addition, the printing operation can be performed immediately after the detection of the consumables, and the waiting time of the user can be reduced as compared with the related art.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS.

In the first embodiment, the resistors 36 for identifying the mounting of the developing devices are arranged on the developing device rotating unit 11 outside the developing devices 47. However, the resistors 36 are not necessarily provided outside the developing devices 47. It is not necessary to arrange them, and resistors 36 having different resistance values may be arranged in each developing device 47.

FIG. 6 is a sectional view of the developing unit 47 and the developing unit rotating unit 11. In this figure, the same elements as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. I do.

The difference from the first embodiment in FIG. 6 is that the resistor 36 is moved to the developing unit 47 and the identifying unit 48 is used.
Has been removed.

FIG. 7 shows the developing device rotating unit 11 shown in FIG.
3 is electrically equivalent to FIG. 3 of the first embodiment. Specifically, the function is exactly the same, except that the connection position of the resistor 36 is changed.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG.

In the first and second embodiments, the developing device 47
Image formation in which the developing unit rotating unit 11 is rotated (moved) so as to make the approximate contact positions of the developing unit and the photosensitive drum 1 the same, and a developing unit 47 necessary for each developing step is selected to perform desired development. Although the example in which the present invention is applied to the apparatus has been described, the present embodiment describes an example in which the present invention is applied to a color image forming apparatus having a different configuration.

FIG. 8 is a sectional view of a color image forming apparatus for forming an image without moving the developing unit. In FIG. 8, elements having the same functions as those shown in FIG. Hereinafter, the description thereof will be omitted.

In FIG. 8, developing units 47Y, 47M, 47C and 47Bk in the first and second embodiments correspond to developing units 3Y, 3M, 3C and 3Bk, respectively. Further, the developing device rotation unit 11 in the first and second embodiments corresponds to the developing device support member 11A. Further, the contacts 21Y, 21Y on the developing unit rotation unit 11 in the first and second embodiments.
1M, 21C, 21Bk and 22Y, 22M, 22C,
22Bk are contact points 27 on the developing device supporting member 11A, respectively.
Y, 27M, 27C, 27Bk and 26Y, 26M, 2
6C and 26Bk. However, in the present embodiment, the contacts 23 and 24 outside the rotary developing unit 11 in the first and second embodiments are unnecessary, and the contacts 26 and 27 are not required.
Is connected to the control circuit 30.

Conventionally, a plurality of detectors for detecting the mounting state of each developing unit and many control lines must be arranged from these detectors to the control circuit. In the embodiment, as shown in FIG. 8, it can be constituted by the minimum necessary parts.

As described above, the present invention can be applied to a color image forming apparatus in which the developing device is not moved.

[0055]

As is apparent from the above description, according to the present invention, in the color image forming apparatus which performs development by moving the position of the developing device, the mounting state of the developing device can be monitored at any time. As described above, there is no need to move the developing unit to check the mounting state of the developing unit, and the effect of shortening the waiting time until printing by the user can be obtained.

In a color image forming apparatus which performs development by moving the position of a developing device, the state of mounting of the developing device at a predetermined position is checked. If this is not possible, the image operation must be stopped immediately.However, in the present invention, since the detection side and the developing device side are always connected, a sufficient retry time is ensured even when detection is not performed well. And the reliability of the color image forming apparatus can be improved.

Further, in a color image forming apparatus which performs development while fixing the position of the developing unit, conventionally, a plurality of detectors for detecting the mounting state of each developing unit and these detector empty control means are provided. However, according to the present invention, inexpensive contact members and only the control lines up to the control means require only the minimum necessary number of components.
The cost of the color image forming apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a developing unit rotation unit of a color image forming apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of a developing device and a developing device rotation unit of the color image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of a developing unit rotation unit of the color image forming apparatus according to Embodiment 1 of the present invention.

FIG. 4 is a diagram illustrating an output voltage of a control circuit of the color image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a timing chart showing an operation state of a control circuit of the color image forming apparatus according to Embodiment 1 of the present invention.

FIG. 6 is a sectional view of a developing device and a developing device rotation unit of the color image forming apparatus according to Embodiment 2 of the present invention.

FIG. 7 is an equivalent circuit diagram of a developing unit rotation unit of the color image forming apparatus according to Embodiment 2 of the present invention.

FIG. 8 is a sectional view of a color image forming apparatus according to Embodiment 3 of the present invention.

FIG. 9 is a cross-sectional view of a conventional color image forming apparatus (color laser beam printer).

FIG. 10 is a perspective view showing a configuration of a developing unit rotation unit of a conventional color image forming apparatus (color laser beam printer).

FIG. 11 is a sectional view of a developing unit and a developing unit rotation unit of a conventional color image forming apparatus (color laser beam printer).

FIG. 12 is an equivalent circuit diagram of a developing unit rotation unit of a conventional color image forming apparatus (color laser beam printer).

FIG. 13 is a timing chart showing an operation state of a control circuit of a conventional color image forming apparatus (color laser beam printer).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photosensitive drum (image carrier) 3 (3M, 3C, 3Y, 3Bk) Developing device 11 Developing device rotation unit (supporting member) 11A Developing device supporting member (supporting member) 21 (21M, 21C, 21Y, 21Bk) Contact point ( First contact member 22 (22M, 22C, 22Y, 22Bk) Contact (first contact member) 23 (23M, 23C, 23Y, 23Bk) Contact (second contact member) 24 (24M, 24C, 24Y, 24Bk) Contact (second contact member) 25 (25A, 25B) 30, 80 Control circuit (control means) 47 (47M, 47C, 47Y, 47Bk) Developing device 48 Identification means

Claims (1)

[Claims] 1. A color image forming apparatus configured to switch between a plurality of detachable developing devices supported by a support member and to develop a latent image on an image carrier, wherein: A first contact member, a second contact member outside the support member that is in contact with and contacts the first contact member,
An identification means unique to the plurality of developing devices, and an electrical connection line on the support member, one end of which is commonly connected to the identification means, and the other end of which is connected to the first contact member. A collar provided with control means for detecting presence / absence of each of the plurality of developing devices via a connection line and the first contact member and the second contact member to vary an image forming operation; Image forming device.