JPH0511579A - Drum driving controller - Google Patents

Abstract

PURPOSE:To lessen irregularities in rotation, and to attain highly accurate rotation by obtaining the relative speed of a photosensitive drum or a sensitized paper holding drum and an exposing position, and controlling the rotational drive of them. CONSTITUTION:A photodetector array 1 being an exposing position detecting means, and a differential amplifier 2 directly or indirectly receive modulated light with which the surface of the photosensitive drum 5 or the sensitized paper holding drum is irradiated, by a photodetector 1a, to detect the exposing position of the modulated light on the drum. A differentiation circuit 4 being a relative speed calculating means requires the relative speed of the photosensitive drum 1 or the sensitized paper holding drum and the exposing position, from electrical signals outputted by the exposing position detecting means 1 and 2, and transmits the calculated relative speed to a speed calculating circuit 5 as a rotation/drive control means. At this time, the speed calculating circuit 5 controls the rotational drive of the photosensitive drum 51 or the sensitized paper holding drum so that the relative speed obtained by the differentiation circuit 4 is prescribed speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming an image by exposing a photosensitive member of a photosensitive drum or a photosensitive paper held on a photosensitive paper holding drum with modulated light according to image data from an exposure device. The present invention relates to an apparatus, and more specifically, to a drum driving apparatus that controls the rotational drive of the photosensitive drum or the photosensitive paper holding drum.

[0002]

2. Description of the Related Art In a wet color image forming apparatus, as shown in FIG. 6, a photosensitive paper transport drum 51 holding a sheet of photosensitive paper 50 on its outer peripheral surface is rotatably supported by a support shaft 52. The following devices are sequentially provided at positions facing the outer peripheral surface of the photosensitive paper transport drum 51. First, the corona charger 53 is installed diagonally above left,
The sheet of photosensitive paper 50 is charged with an electrostatic charge. Next, an exposure device 54 is installed on the left side of the photosensitive paper transport drum 51, and exposes the sheet-shaped photosensitive paper 50 charged by the corona charger 53 to form an electrostatic latent image.

Below the photosensitive paper transport drum 51, a pre-wet roller 55 that contacts the sheet-shaped photosensitive paper 50 to prevent background stains with a developer solvent, and a sheet-shaped photosensitive paper 50 wet with the developer solvent. Developing device 56 (56Y, 56M, 56C, 56B) for developing the toner with a developing solution, and a drum cleaning device 57 for removing the excess developing solution adhering to the outer peripheral surface of the photosensitive paper transport drum 51 and the toner fixed and laminated. Are arranged. Further, in the rear of the drum cleaning device 57, the sheet-shaped photosensitive paper 5 after development is formed.
A static eliminator 58 for removing the electric charge remaining at 0 is provided.

The developing device 56 includes the sheet-shaped photosensitive paper 5
A developing electrode 59 that supplies a developing solution facing 0, a squeezing roller 60 that removes the excess developing solution remaining on the surface of the sheet of photosensitive paper 50, and a developing solution tank 61 that stores the developing solution. And is arranged below the photosensitive paper transport drum 51 by the number of developers required for color image formation (four in the conventional example). As shown in the drawing, each developing device 56 has a developing electrode 59 with a slight distance from the photosensitive paper transport drum 51, and can be raised and lowered sequentially to the opposing position. At this time, the squeeze roller 60 is pressed against the lower surface of the photosensitive paper transport drum 51.

Further, on the upper right of the photosensitive drum 50,
A cartridge 63 for storing the roll-shaped photosensitive paper 62, a paper feed roller 64 for cutting the roll-shaped photosensitive paper 62 into a desired length and supplying it as the sheet-shaped photosensitive paper 50 to the photosensitive-paper conveying drum 51, a cutter 65, a guide 66 are arranged in order in the direction of the photosensitive paper transport drum 51. On the upper left side, a peeling claw 67 for peeling the sheet-shaped photosensitive paper 50 on which an image has been formed and having an image formed thereon from the photosensitive paper transport drum 51, and a discharge belt 68 for discharging the sheet-shaped photosensitive paper 50 are arranged. The sheet photosensitive paper 50 is discharged to the discharge tray 70 attached to the housing 69. Further, a front panel 71 is arranged on the front surface of the housing 69.

Next, the operation of the wet color image forming apparatus will be described.

When the operator operates a copy key arranged on the front panel 71, the roll-shaped photosensitive paper 62 in the cartridge 63 is transferred to the paper feed roller 64 and the cutter 6.
5, cut to a desired length by the guide 66, fed as the sheet-shaped photosensitive paper 50 to the photosensitive drum 50, and held on the outer peripheral surface of the photosensitive paper transport drum 51 by a method using negative pressure. In this state, the photosensitive paper transport drum 51 is rotated in the direction of the arrow by the drum driving device, and at the same time, the sheet-shaped photosensitive paper 50 is first charged by the corona charger 5.
The surface 3 is given an electrostatic charge to be charged.

Then, the sheet-shaped photosensitive paper 50 is wetted with a developer solvent by a pre-wet roller 55 after an electrostatic latent image is formed on the surface by the exposure device 54. Subsequently, when the sheet of photosensitive paper 50 passes through the developing electrode 59, it is developed with a developing solution and the electrostatic latent image is visualized. Excessive developer remaining on the surface of the sheet of photosensitive paper 50 after development is removed and collected by the squeeze roller 60. Further, the sheet-shaped photosensitive paper 50 removes the electric charge remaining on the surface from the static eliminator 5.
After being removed by 8, the next color process is performed.

Simultaneously with the above steps, the photosensitive paper transport drum 5
Cleaning process 1 is being performed. The photosensitive paper transport drum 5
After the rear end of the sheet of photosensitive paper 50 has passed through the squeeze roller 60 with the rotation of 1, the developing device 56 separates from the lower surface of the photosensitive paper transport drum 51 with the movement of switching to the next step. When the rear end of the sheet of photosensitive paper 50 passes through the drum cleaning device 57, the drum cleaning device 57 contacts the outer peripheral surface of the photosensitive paper transport drum 51 and adheres to the outer peripheral surface of the photosensitive paper transport drum 51. The excess developer and the fixed and laminated toner are removed.

A color image can be obtained by repeating the image forming process and the cleaning process as many times as necessary, and the sheet-shaped photosensitive paper 50 is separated from the photosensitive paper conveying drum 51 by the separating claw 67, and the sheet is discharged. The belt 68 discharges the paper to a paper discharge tray 70 attached to the housing 69, and all steps are completed.

As shown in FIG. 5, the block diagram of the conventional drum drive motor control is such that the speed signal from the encoder 81 fixed to the motor shaft of the drum drive motor 80 is fed back to the speed difference detection circuit 82 to be used as a reference. Based on the speed difference from the signal, the compensation amplifier circuit 83 and the drive circuit 84 control the drum drive motor 80, and the rotation of the drum drive motor 80 is transmitted to the conveying drum 51 by transmission means such as a gear. The transport drum 51 was rotationally driven.

[0012]

However, in the case of mounting the encoder on the motor shaft of the drum drive motor to control the rotation, even if the motor shaft of the drum drive motor is rotating at a constant speed, The transmission system to the photosensitive drum or photosensitive paper holding drum is not an ideal transmission system due to gear backlash or lack of accuracy, and uneven speed occurs in the peripheral speed of the photosensitive drum or photosensitive paper holding drum. There was a problem to do.

The present invention has been made in order to solve the above-mentioned problems, and provides a drum driving device of an image forming apparatus for rotating a photosensitive drum or a photosensitive paper holding drum with high accuracy with very little unevenness in rotation. The purpose is to do.

[0014]

In order to achieve this object, a drum driving device of the present invention comprises an exposure position detecting means for detecting the exposure position of the modulated light on the surface of the photosensitive drum or the photosensitive paper holding drum. A relative speed calculation means for obtaining a relative speed between the exposure position and the photosensitive drum or the photosensitive paper holding drum from an electric signal output from the exposure position detection means; and the relative speed calculated by the relative speed calculation means is predetermined. And a rotational drive control means for controlling the rotational drive of the photosensitive drum or the photosensitive paper holding drum so that the speed is set to.

[0015]

In the drum driving device of the present invention configured as described above, the exposure position detecting means directly applies the modulated light radiated on the surface of the photosensitive drum or the photosensitive paper holding drum to the exposure position detecting means.
Alternatively, the light receiving element is indirectly received to detect the exposure position of the modulated light on the drum.

The relative speed calculation means obtains the relative speed between the exposure position and the photosensitive drum or the photosensitive paper holding drum from the electric signal output from the exposure position detection means, and the calculated relative speed is given to the rotation drive control means. introduce.

The rotation drive control means controls the rotation drive of the photosensitive drum or the photosensitive paper holding drum so that the relative speed obtained by the relative speed calculation means becomes a predetermined speed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a structure near the photosensitive paper transport drum 51.

As shown in FIG. 2, the light receiving element array 1 is embedded in the photosensitive paper conveying drum 51 on the side (right side) of the winding position of the sheet of photosensitive paper 50 on the surface of the photosensitive paper conveying drum 51. Has been done. The light receiving element array 1 has the configuration shown in FIG. 3, and includes a light receiving element 1a connected to the inverting input of the differential amplifier 2 and a light receiving element 1b connected to the non-inverting input of the differential amplifier 2. It has a structure in which they are arranged alternately.

The width of each of the light-receiving elements 1a and 1b is equal to the interval between the scanning lines of the scanning laser light emitted from the exposure device 54, and a seam comes to the center of the ideal position of the scanning lines of the scanning laser light. Are arranged as follows. Therefore, when the scanning laser beam performs the main scanning at the ideal position, the light receiving element 1a
And 1b receive the same amount of light, the output of the differential amplifier 2 is zero. However, when the scanning laser beam shifts to the upper or lower side, the amounts of light received by the light receiving elements 1a and 1b do not become equal. Therefore, the output of the differential amplifier 2 is not zero, and a signal corresponding to the distance between the scanning position of the scanning laser light and the ideal position is output. That is, in this embodiment, the light receiving element array 1 and the differential amplifier 2 form an exposure position detecting means.

FIG. 4 is a block diagram according to the present invention.
Light receiving elements 1 arranged next to each other in the light receiving element array 1
The differential amplifier 2 to which the signals a and 1b are input is input to the sample and hold circuit 3 as the scanning position signal of the scanning laser light based on the difference between the signals from the light receiving elements 1a and 1b.
The sample and hold circuit 3 samples and holds the main scanning position signal at the timing when the scanning laser light irradiates the light receiving element array 1. The main scanning position signal held by the sample and hold circuit 3 is then output to the differentiating circuit 4, which differentiates the scanning position signal of the scanning laser light to generate a relative speed signal in the sub-scanning direction. To do. That is, in this embodiment, the differentiating circuit 4 constitutes a relative speed calculating means.

The relative speed signal in the sub-scanning direction output from the differentiating circuit 4 is input to the speed calculating circuit 5 as a feedback signal. The speed calculation circuit 5 creates a speed signal to be sent to the compensation amplification circuit 83 from the reference speed signal generated from a reference speed signal generator (not shown) and the relative speed signal. That is, in the present embodiment, the speed calculation circuit 5 constitutes the rotation drive control means.

Next, the operation will be described.

When the operator operates the copy key arranged on the front panel 71, the roll-shaped photosensitive paper 62 in the cartridge 63 is transferred to the paper feed roller 64 and the cutting device 6.
5. The sheet is cut to a desired length by the guide 66, fed as the sheet-shaped photosensitive paper 50 to the photosensitive drum 51, and held on the outer peripheral surface of the photosensitive paper transport drum 51 by a method using negative pressure. In this state, the photosensitive paper transport drum 51 is rotated in the direction of the arrow by the drum driving device, and at the same time, the sheet-shaped photosensitive paper 50 is first charged by the corona charger 5.
The surface 3 is given an electrostatic charge to be charged.

Thereafter, the sheet-shaped photosensitive paper 50 is wetted with a developer solvent by a pre-wet roller 55 after an electrostatic latent image is formed on the surface by the exposure device 54. Subsequently, when the sheet of photosensitive paper 50 passes through the developing electrode 59, it is developed with a developing solution and the electrostatic latent image is visualized. Excessive developer remaining on the surface of the sheet of photosensitive paper 50 after development is removed and collected by the squeeze roller 60. Further, the sheet-shaped photosensitive paper 50 removes the electric charge remaining on the surface from the static eliminator 58.
And the image is formed on the sheet of photosensitive paper 50.

During the image forming process, the sheet-shaped photosensitive paper 5
The photosensitive paper transport drum 51 wound with 0
Rotate at (m / s). The photosensitive paper transport drum 51 has a peripheral speed
The relative speed in the sub-scanning direction between the photosensitive paper transport drum 51 and the laser scanning light when the exposure device 53 is rotating at (m / s) and scanning exposure is performed while the exposure device 53 is stationary without vibrating is υ (m / s). )
Is. At this time, the photosensitive paper transport drum 51 is actually "υ +" including a slight rotation fluctuation Δυ1 for mechanical reasons.
It rotates at Δυ1 ”(m / s). Also, the exposure device 54
Also includes a velocity fluctuation Δυ2 in the sub-scanning direction due to a slight vibration for mechanical reasons. Therefore, the relative velocity between the exposure device 10 and the photosensitive paper transport drum 51 is “υ + Δυ3”.
(M / s) (where Δυ3 = Δυ1 + Δυ2).

When the sheet-shaped photosensitive paper 50 starts to be exposed by the exposure device 53, the scanning laser light emitted from the exposure device 53 to the sheet-shaped photosensitive paper 50 is also applied to the light receiving element array 1. The scanning line by the first laser beam is the light receiving element array 1
After passing through, the differential amplifier 2 detects the difference between the passing position of the scanning laser light at that time and the ideal expected passing position. When the next scanning laser light passes through the light receiving element array 1 again, the difference between the passing position of the scanning laser light and the ideal expected passing position is detected again by the differential amplifier 2, and the sample
It is held by the hold circuit 3. When these pieces of information are differentiated by the differentiating circuit 4, a variation component Δν 3 of the relative speed between the photosensitive paper transport drum 51 and the exposure device 53 is obtained.

A reference speed signal generated from a reference signal generator (not shown) is input to the speed calculation circuit 5, and the speed calculation circuit 5 calculates the speed signal from the reference signal and the relative speed υ + Δυ3, and the compensation amplifier 83 To enter. The compensation amplifier 83 compensates and amplifies the speed signal and sends it to the drive circuit 84. The drive circuit 84 generates a drive signal corresponding to the speed signal and sends the drive signal to the drum drive motor 80 to rotate the drum drive motor 80. By the rotation of the drum drive motor 80, the transport drum 51 is rotated at a predetermined rotation speed via a transmission system such as a gear.

In the present embodiment, the light receiving element array 1 in which the light receiving elements 1a and 1b are alternately arranged is used as the exposure position detecting means, but the present invention is not limited to this, and as shown in FIG. 4, for example. On the surface of the photosensitive paper transport drum 51, a reflector 11 having reflective surfaces and non-reflective surfaces alternately arranged is attached, and light receiving elements 11a and 11b are arranged beside it, and outputs of the light receiving elements 11a and 11b are output. It can also be realized by inputting to the differential amplifier 2 and using this as the exposure position detecting means.

[0031]

As is clear from the above description,
In the present invention, the exposure position detecting means for detecting the exposure position of the modulated light on the surface of the photosensitive drum or the photosensitive paper holding drum and the electric signal output from the exposure position detecting means are used to hold the photosensitive drum or the photosensitive paper holding means. Relative speed calculating means for calculating the relative speed between the drum and the exposure position, and controlling the rotational drive of the photosensitive drum or the photosensitive paper holding drum so that the relative speed calculated by the relative speed calculating means becomes a predetermined speed. By providing the rotation drive control means, the photosensitive drum or the photosensitive paper holding drum,
Considering the vibration of the exposure system, the uneven rotation is extremely small,
It is possible to provide a drum driving device of an image forming apparatus that rotates with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of an electric circuit according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the vicinity of the drum according to the first embodiment of this invention.

FIG. 3 is an enlarged configuration diagram showing a configuration near a light receiving element array according to a first embodiment of the present invention.

FIG. 4 is an enlarged configuration diagram showing a configuration near a reflector according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a conventional electric circuit.

FIG. 6 is a configuration diagram showing an overall configuration of an image forming apparatus.

[Explanation of symbols]

 1 light receiving element array 1a light receiving element 1b light receiving element 2 differential amplifier 3 sample / hold circuit 4 differentiating circuit 5 speed calculation circuit 11 reflection pair 11a light receiving element 11b light receiving element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location H04N 1/29 Z 9186-5C

Claims (1)

Claim: What is claimed is: 1. An image forming method for forming an image by exposing modulated light according to image data from an exposure device onto a photosensitive member of a photosensitive drum or a photosensitive paper held by a photosensitive paper holding drum. In the apparatus, the exposure position detecting means for detecting the exposure position of the modulated light on the surface of the photosensitive drum or the photosensitive paper holding drum, and the photosensitive drum or the photosensitive paper holding drum from the electric signal output by the exposure position detecting means. Relative speed calculation means for calculating relative speed with respect to the exposure position, and rotational drive for controlling rotational drive of the photosensitive drum or the photosensitive paper holding drum so that the relative speed calculated by the relative speed calculation means becomes a predetermined speed. A drum drive control device comprising: a control unit.