JP2001350308A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus capable of realizing highly accurate photoconductor driving. SOLUTION: A printing color mode detecting means for judging a printing color mode, a plurality of photoconductor driving means for driving each photoconductor, and the plurality of driving information signals output from the plurality of photoconductor driving means. A plurality of photosensitive member surface drive information detecting means for detecting drive information on the surface of the photosensitive member; and a plurality of photosensitive member surface drive information detecting means for driving the plurality of photosensitive members. And a plurality of photoconductor load detecting means for detecting a load state of the plurality of photoconductors, and controlling the feedforward controller based on detection results from the plurality of photoconductor load detecting means. The configuration was characterized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a page printer for printing image data using dots.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus employing an electrophotographic system, a photosensitive member as an image carrier is charged by a charger, and the charged photosensitive member is irradiated with light in accordance with image information to form a latent image. An image is formed, the latent image is developed by a developing device, and the developed toner image is transferred to a sheet material or the like to form an image.

On the other hand, in accordance with colorization of an image, a plurality of image forming stations for performing the respective image forming processes are provided, and a cyan image, a magenta image, a yellow image,
Preferably, a tandem-type color image forming apparatus for forming a full-color image by forming each color image of a black image on each image carrier and superimposing and transferring each color image on a sheet material at a transfer position of each image carrier Has also been proposed. First, a process of obtaining a color image by the tandem method will be described with reference to FIG.

FIG. 5 is a configuration diagram of a conventional color image forming apparatus.

In FIG. 5, a color image forming apparatus
Image forming stations 1k, 1y, 1m, 1c are arranged, and each image forming station 1k, 1y, 1m, 1
c denotes photosensitive drums 2k, 2y, 2m as image carriers.
2c, around which a dedicated charging means 3 is provided.
k, 3y, 3m, 3c, developing means 4k, 4y, 4m, 4
c, cleaning means 5k, 5y, 5m, 5c, exposure means 6k, 6y, 6m, 6c of a scanning optical system for irradiating each photosensitive drum with light corresponding to image information, and a transfer unit in transfer means 7. 8k, 8y, 8m and 8c are arranged respectively.

Here, the image forming stations 1k, 1
y, 1m, and 1c are for forming a yellow image, a magenta image, a cyan image, and a black image, respectively. 9k, 9y, 9m, and 9c are output. An untransferred belt-shaped intermediate transfer belt 12 supported by support rollers 10 and 11 is provided below the photosensitive drums 2k, 2y, 2m and 2c so as to pass through the image forming stations 1k, 1y, 1m and 1c. It is arranged and moves in the direction of arrow A.
The image data processing unit 13 determines a print color mode and the like, and outputs image data of a designated color.

The sheet material 15 stored in the sheet feeding cassette 14 is fed by a sheet feeding roller 16 and discharged to a sheet discharge tray (not shown) via a sheet material transfer roller 17 and a fixing means 18. You.

In the above arrangement, first, the photosensitive drum 2k is charged by a known electrophotographic process means such as the charging means 3k of the image forming station 1k and the exposure means 6k.
After a black component color latent image of image information is formed thereon, it is visualized as a black toner image by a developing material having black toner by a developing unit 4k, and the black toner image is formed on the intermediate transfer belt 12 by a transfer unit 8k. Transcribed.

On the other hand, while the black toner image is being transferred to the intermediate transfer belt 12, a latent image of a yellow component color is formed in the image forming station 1y, and a yellow toner image of yellow toner is obtained by the developing means 4y. 8
y, and is superimposed on the black toner image previously transferred on the intermediate transfer belt 12.

Hereinafter, the magenta toner image and the cyan toner image are formed in the same manner, and when the superposition of the four color toner images on the intermediate transfer belt 12 is completed, the paper feed cassette The four color toner images are collectively transferred and conveyed by a sheet material transfer roller 17 onto a sheet material 15 such as paper supplied from the fixing device 1.
8 to form a full-color image on the sheet material 15. Each of the photoreceptor drums 2k, 2y, 2m, and 2c after the completion of the transfer is a cleaning unit 5k, 5
At y, 5m and 5c, the residual toner is removed, and the printing operation is completed in preparation for the next image formation to be performed subsequently.

As described above, the tandem-type color image forming apparatus has an image forming unit for each color, which is advantageous for speeding up. However, there is a problem in how to properly perform registration (registration) of each image formed by different image forming units. This is because a shift in the image forming position of the four colors transferred to the sheet material or the like finally appears as a position shift or a change in color tone. It is apparent that color misregistration actually occurs due to the attachment / detachment of the image forming stations 1k, 1y, 1m, and 1c, the movement of the image forming apparatus, and the mounting error of the scanning optical system.

During the image forming operation, the photosensitive drum 2
k, 2y, 2m, and 2c are also driven, and the degree of color misregistration depends on the driving accuracy. Therefore, to reduce the degree of color misregistration, the photosensitive drums 2k, 2y, 2m,
2c needs to be driven with high accuracy. Hereinafter, the driving operation of the conventional photosensitive drum will be described. Here, the driving of the photosensitive drum 2k will be described for simplicity. Incidentally, the driving method of the photosensitive drums 2y, 2m, 2c is also completely the same as that of the photosensitive drum 2k, so that the detailed description is omitted.

FIG. 6 is a block diagram of a conventional photosensitive drum drive motor control. At the time of starting the photosensitive drum driving, first, the feedback controller 6a sets the photosensitive drum driving motor speed setting value to the speed setting unit 6b. This set value is a value corresponding to the set rotation speed of the photosensitive drum drive motor. Next, a signal for driving the photosensitive drum drive motor 6d is generated by the driver unit 6c via a DA converter or the like in the driver unit 6c, and the drive of the photosensitive drum drive motor 6d is performed. Be started.
When the drive of the photosensitive drum drive motor 6d is started, a drive information signal is output from an internal encoder (not shown) and is again input to the feedback controller 6a.
When the drive of the photosensitive drum drive motor 6d is started, the photosensitive drum 6f is driven via a transmission system 6e such as a gear or a belt. When the photosensitive drum 6f is driven,
Drive information on the surface of the photosensitive drum is acquired by a photosensitive drum drive information detector 6g provided on the rotation axis of the photosensitive drum 6f, and is input to the feedforward controller 6h. The feedforward controller 6h acquires the circulation data of the output from the photosensitive drum drive information detection unit 6g, and performs a filtering process or the like to generate feedforward data. In generating the feedforward data, a so-called delay time from when the photosensitive drum drive motor starts driving to when the photosensitive drum actually starts rotating via the transmission system is considered. Then, by adding this feedforward data to the output of the feedback controller 6a, steady speed fluctuation of the photosensitive drum 6f is suppressed.

FIG. 7 is a principle diagram of a conventional feedforward controller. It is assumed that the speed fluctuation of the photosensitive drum to be subjected to the feedforward control is detected by the photosensitive drum drive information detecting unit 6g as shown in FIG. Based on the detected data, as shown in FIG. 7B, reverse-phase data that cancels the speed fluctuation component obtained in FIG. 7A is generated. This is so-called feed-forward data, and the feed-forward data is added by synchronizing with a predetermined reference signal (by controlling the origin of the graph shown in the drawing so as to match the origin) as shown in FIG.
As shown in (c), the speed fluctuation is canceled out, and the photosensitive member can be driven with high accuracy. Actually, the addition timing of the feedforward data is controlled in consideration of a delay time due to a mechanism transmission system such as a gear or a belt interposed between the photoconductor drive motor and the photoconductor drum.

The drive accuracy is improved by the above-described series of drive controls to reduce color misregistration.

[0016]

However, in the above-mentioned conventional configuration, the delay time varies depending on the load on the photoconductor, and the delay time depends on a predetermined fixed photoconductor load. However, when the load fluctuation of the photoconductor occurs due to a decrease in toner, a correct delay time cannot be obtained, and erroneous feedforward data is added to the feedback controller.

The present invention has been made to solve these problems, and an object of the present invention is to measure the load on a photoconductor and set a delay time in accordance with the load to reset the photoconductor. Even if a load change occurs, more accurate feedforward data can be added to the feedback controller, and highly accurate photoconductor drive can be realized.

[0018]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of image stations having a photoreceptor and developing means for developing a latent image formed on the photoreceptor as a toner image. And a plurality of exposure means for irradiating each photoconductor in the plurality of image stations with light to form a latent image, and a transfer means for transferring and conveying a toner image formed in the plurality of image stations to a transfer material A color image forming apparatus for forming a composite image by superimposing toner images visualized on the plurality of image stations sequentially on a transfer material, wherein a printing color is used to enable the image station of a designated color. A print color mode detection unit for determining a mode, a plurality of photoconductor drive units for driving each photoconductor in the plurality of image stations, and an output from the plurality of photoconductor drive units. A feedback controller that drives the plurality of photoconductors according to the drive information signal, a plurality of photoconductor surface drive information detection units that detect drive information of the surface of the photoconductor, and a plurality of photoconductor surface drive information detection units. A feed forward controller that drives the plurality of photoconductors; and a plurality of photoconductor load detection units that detect a load state of the plurality of photoconductors, wherein the feed is performed based on a detection result from the plurality of photoconductor load detection units. The configuration is such that the forward controller is controlled.

With the above configuration, it is possible to provide a color image forming apparatus capable of realizing a highly accurate drive control system.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The invention as set forth in claim 1 of the present invention comprises a plurality of image stations having a photoreceptor and a developing means for developing a latent image formed on the photoreceptor into a toner image. A plurality of exposure means for irradiating light to each photoconductor in a plurality of image stations to form a latent image, and a transfer means for transferring and conveying a toner image formed in the plurality of image stations to a transfer material, In a color image forming apparatus that sequentially superimposes toner images visualized in a plurality of image stations on a transfer material to form a composite image, a print color mode for determining a print color mode to enable an image station of a designated color. Mode detection means, a plurality of photoconductor driving means for driving each photoconductor in a plurality of image stations,
A feedback controller that drives the plurality of photoconductors based on drive information signals output from the plurality of photoconductor drive units, a plurality of photoconductor surface drive information detection units that detect drive information on the surface of the photoconductor, and the plurality of photoconductors A feedforward controller that drives the plurality of photoconductors from the surface drive information detection unit, and a plurality of photoconductor load detection units that detect a load state of the plurality of photoconductors, and a detection result from the plurality of photoconductor load detection units An image forming apparatus characterized by controlling a feedforward controller by:
An image forming apparatus capable of realizing a highly accurate drive control system can be provided.

According to a second aspect of the present invention, there is provided an image forming apparatus in which the above-described series of control sequences is stored in a non-volatile memory. Can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a photosensitive drum drive motor control unit according to an embodiment of the present invention, FIG. 2 is a block diagram of a photosensitive drum load detecting unit according to the embodiment of the present invention, and FIG. FIG. 4 is a block diagram of a feedforward controller according to an embodiment of the present invention.

The process of obtaining a color image according to the embodiment of the present invention is the same as in the prior art, and a detailed description is omitted.

Next, a drive control method of the photosensitive drum drive motor according to the embodiment of the present invention will be described with reference to FIG.

First, the feedback controller 1a sets a photosensitive drum drive motor speed set value to the speed setting section 1b. This set value is a value corresponding to the set rotation speed of the photosensitive drum drive motor. Next, a signal for driving the photosensitive drum drive motor 1d is generated by the driver unit 1c via a DA converter or the like using the photosensitive drum drive motor speed set value, and the drive of the photosensitive drum drive motor 1d is performed. Be started. When the drive of the photosensitive drum drive motor 1d is started, a drive information signal is output from an internal encoder (not shown) and input to the feedback controller 1a. When the drive of the photosensitive drum drive motor 1d is started, the photosensitive drum 1f is driven via a transmission system 1e such as a gear or a belt. When the photosensitive drum 1f is driven, drive information on the surface of the photosensitive drum is acquired by a photosensitive drum drive information detecting unit 1g provided on the rotation axis of the photosensitive drum 1f, and the feedforward controller 1
h. Further, the load on the photosensitive drum is detected by the photosensitive drum load detecting section 1i. A toner remaining amount detecting device (not shown) is used for detecting the load on the photosensitive drum. That is, the signal level of the toner remaining amount notification signal from the toner remaining amount detecting device (the signal level increases as the amount of toner increases,
The photoreceptor load is calculated according to the signal level as the toner decreases. Further, a delay time of the transmission system 1e is calculated from the photoconductor load, or a delay time corresponding to the toner amount is prepared in advance as a table by a plurality of data acquisition experiments. Feed forward controller 1
In h, feed-forward data is generated by performing a filtering process or the like based on the output from the photosensitive drum load detection unit 1i. The feedforward data is added to the feedback controller 1a to control the photosensitive drum 1f in response to the photosensitive member load fluctuation.
The steady-state speed fluctuation is suppressed.

Next, the operation of detecting the photosensitive drum load in the present invention will be described with reference to FIG. 2 in FIG.
a is a photosensitive drum. A toner cartridge storing toner for image formation is mounted on the photosensitive drum 2a. The toner remaining amount detector 2b manages the amount of toner in the toner cartridge. The toner remaining amount detection section outputs a prescribed signal level according to the amount of toner in the toner cartridge. That is, when the toner cartridge is full of toner, the maximum signal level (5 V in this embodiment) is used.
When the image forming operation is repeated and the toner is consumed, the output signal level is reduced in accordance with the consumed toner amount. (Not shown) The photoconductor load calculation unit 2c calculates the delay time of the mechanism transmission system according to the photoconductor load in accordance with the output signal level from the toner remaining amount detection unit 2b. Then, the delay time obtained by the photoconductor load calculator 2c is input to the feed forward controller 2d to generate feed forward data.

Next, the relationship between the photosensitive drum load and the delay time in the present invention will be described with reference to FIG. In the graph of FIG. 3, the horizontal axis represents the photoconductor load, and the vertical axis represents the delay time. The delay time increases as the photoconductor load increases. The slope of this graph is obtained by performing a plurality of experiments while varying the load on the photoconductor, that is, the amount of toner in the toner cartridge, and is stored in a predetermined memory area as a table in advance.

Next, the control operation of the feedforward controller according to the present invention will be described with reference to FIG.
In FIG. 4, in a feedforward controller 4a, a photoconductor speed fluctuation measuring unit 4b for acquiring a photoconductor speed fluctuation and a photoconductor load measuring unit 4c for measuring a photoconductor load.
Then, feedforward data is generated based on both output results. Further, the photoreceptor load measuring unit 4c calculates a delay time according to a graph (data table stored in a predetermined memory area) showing the relationship between the photoreceptor load and the delay time shown in FIG. Pass the data to. Then, the feedforward data is generated by the feedforward data generation unit 4e using the photoconductor speed fluctuation data obtained by the photoconductor speed fluctuation measurement unit 4b and the photoconductor load data obtained by the photoconductor load measurement unit 4c. Generated. The feedforward data obtained here is data that takes into account not only fluctuations in the speed of the photoconductor, but also fluctuations in the delay time according to the load on the photoconductor, so that the optimum feedforward data can always be referred to.

[0029]

As described above, according to the present invention, the photoconductor load is measured and feedforward data is generated in consideration of the delay time corresponding to the photoconductor load fluctuation. It is possible to cope with fluctuations in the delay time of the mechanism transmission system due to fluctuations in the body load, and it is possible to obtain an image forming apparatus that can realize highly accurate photoconductor driving.

[Brief description of the drawings]

FIG. 1 is a block diagram of a photosensitive drum drive motor control according to an embodiment of the present invention.

FIG. 2 is a block diagram of a photosensitive drum load detecting unit according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a photosensitive drum load and a delay time according to the embodiment of the present invention.

FIG. 4 is a block diagram of a feedforward controller according to the embodiment of the present invention.

FIG. 5 is a configuration diagram of an embodiment of the present invention and a conventional color image forming apparatus.

FIG. 6 is a conventional photosensitive drum drive motor control block diagram.

FIG. 7 is a principle diagram of a conventional feedforward controller.

[Explanation of symbols]

 1k, 1y, 1m, 1c Image forming station 2k, 2y, 2m, 2c Photoconductor 3k, 3y, 3m, 3c Charging means 4k, 4y, 4m, 4c Developing means 5k, 5y, 5m, 5c Cleaning means 6k, 6y, 6m, 6c Exposure unit 7 Transfer unit 8k, 8y, 8m, 8c Transfer unit 9k, 9y, 9m, 9c Light 10, 11 Support roller 12 Intermediate transfer belt 13 Resist pattern generation unit 14 Pattern detection unit 15 Position shift correction unit 16 Supply Paper cassette 17 sheet material 18 paper feed roller 19 sheet material transfer roller 20 fixing means

Claims (2)

[Claims] A plurality of image stations each having a photoconductor, a developing unit for developing a latent image formed on the photoconductor as a toner image, and applying light to each photoconductor in the plurality of image stations. A plurality of exposure means for irradiating and forming a latent image; and a transfer means for transferring and conveying a toner image formed in the plurality of image stations to a transfer material, and visualized in the plurality of image stations. In a color image forming apparatus for forming a composite image by sequentially superimposing toner images on a transfer material, a print color mode detecting means for determining a print color mode to enable the image station of a designated color; A plurality of photoconductor driving means for driving each of the photoconductors in the station; and a drive for driving the plurality of photoconductors based on a driving information signal output from the plurality of photoconductor driving means. A feedback controller, a plurality of photosensitive member surface drive information detecting means for detecting drive information of the surface of the photosensitive member, and a feedforward controller for driving the plurality of photosensitive members from the plurality of photosensitive member surface drive information detecting means. A plurality of photoconductor load detecting means for detecting a load state of the plurality of photoconductors, and controlling the feedforward controller based on detection results from the plurality of photoconductor load detecting means. apparatus. 2. An image forming apparatus according to claim 1, wherein said series of control sequences are stored in a nonvolatile memory.