JPS63221362A - Recorder - Google Patents

Abstract

PURPOSE:To prevent uneven speeds of plural driving sources and to obtain high-quality images by subjecting the reference signal to control means for the speeds of the driving sources to frequency division according to the accuracy of the control means. CONSTITUTION:A common reference frequency signal FV is generated by a quartz oscillator 53 is supplied through a frequency divider 54 for drum control and a frequency divider 55 for belt control to respective PLL control parts 52. The PLL control parts 52 control rotations by comparing the signals divided down from the frequency signal FV and the frequency signal FG fed back thereto. The control without having the uneven rotations relative to each other is, therefore, possible without necessitating discrete provision of frequency generating means. Since the PLL control part for the drum dispenses with an encoder of the accuracy lower than the accuracy of an encoder for the belt, the number of using the high-accuracy encoders is decreased by providing the frequency divider to supply the reference frequency corresponding to the resolution of the encoders for the respective PLL control parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to control of a drive source in a recording apparatus.

[Background Art] Some color recording devices, such as laser beam printers, have photosensitive drums for magenta, cyan, yellow, and black colors. In such a device, when the rotational speed of each drum is controlled by PLL using different motors, if there are variations in the reference frequency of the control circuit of each motor, the rotation of each drum cannot be accurately controlled, which may cause color misalignment. turn into.

Therefore, it is conceivable to use a common reference frequency for each motor control circuit. However, since the recording paper conveyance belt uses a non-rigid material, there is a risk that the rate of speed fluctuation will be greater than that of a drum system made of a rigid body.
A high-resolution encoder is required, which increases the cost of the device.

[Objective] The present invention was made in view of the above points, and an object of the present invention is to provide a device that can accurately control a plurality of drive sources with an inexpensive configuration.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a sectional view illustrating an example of a four-drum type laser beam printer. In this figure, 21 is the main body of the apparatus, 22 is a paper feed cassette, and recording paper 24 is fed by driving a paper feed roller 23 .

41 is a laser unit that forms a latent image on the cyan photosensitive drum 45c according to color image data. 41M
is a laser unit that forms a latent image on the magenta photosensitive drum 45M according to color image data. 41v is a laser unit e4'! that forms a latent image on the yellow photosensitive drum 45Y according to the color image data. LL is a laser unit that forms a latent image on the black photosensitive drum 45BL according to color image data. 42°.

42M, 42y, and 4211L are toner hoppers filled with cyan, magenta, yellow, and black toners, respectively. 43 is a conveyor belt, and the recording paper 24
transport. 44C, 44M.

44Y and 44111L are transfer chargers that transfer the toner image onto the recording paper 24 being conveyed. Note that each of the laser units 41c, 41M, 41y, and 41[IL has a polygon mirror (polygon mirror) to be described later, and horizontally scans the laser beam in the main scanning direction.

Uniformly charged photosensitive drums 45C and 45M.

Laser unit 41c is attached to 45Y and 4511L.

41,. 41Y, 41. Laser light that turns on and off according to color image A3 is irradiated from L, and the photosensitive drum 45
Latent images are formed on toner hoppers 42c, 42M, 45M, 45Y, and 45BL.

42Y, 42! It is developed and visualized using cyan, magenta, yellow, and black toners filled in the IL. Transfer chargers 44c and 44M are placed on the recording paper 24 on which the toner image is conveyed.

44,. 448L transfers it. Next, the toner image is fixed in the fixing device 34 to form the color image on the recording paper 2.
4 is discharged onto the paper discharge tray 35.

FIG. 3 is a diagram showing the vicinity of the belt 43 that conveys the recording paper 24. The belt 43 is driven by a motor 46, and the speed of the belt 43 is detected by an encoder 47 connected to a pickup roller 48.

FIG. 4 is a diagram showing the vicinity of the photosensitive drum 45. The photosensitive drum 45 is driven by a motor 50 via a rubber roller 51, and an encoder 49 disposed on the drum center axis.
The speed is detected.

FIG. 5 is a block diagram illustrating a control configuration using the motor and encoder shown in FIGS. 3 and 4. FIG. The frequency signal FG detected by the rotary encoder 47.49 is fed back to the PLL control unit 52 and compared with the reference frequency signal FV of the oscillator 53 to control the current supplied to the motor 46.50. This control section 52 is provided on the belt and each photosensitive drum. The reference frequency FV is divided according to the resolution of the detector (encoder).

FIG. 1 shows details of the PLL control circuit. In this figure, a common reference frequency signal F generated from a crystal oscillator 53
V is supplied to each PLL control section 52 through a frequency divider 54 for drum control and a frequency divider 55 for belt control. As can be seen from this figure, each PLL control section 52 has a common reference frequency F.
Since the rotation is controlled by comparing the signal frequency-divided from V and the fed-back frequency signal FG, there is no need for each to have a frequency generating means, and rotation can be controlled without unevenness.

In addition, since the PLL control section of the drum requires a lower-precision encoder than that of the belt, by providing a frequency divider that supplies a reference frequency according to the resolution of the encoder of each PLL control section, it is possible to eliminate the need for an expensive high-precision encoder. The number of points used can be reduced.

[Effect] As explained above, according to the present invention, means for supplying a common frequency signal to a plurality of speed/speed control means is provided, and the common frequency is adjusted to a reference frequency according to the control accuracy of each speed control means. Since the frequency dividing means is provided, it is possible to prevent speed unevenness of a plurality of different types of drive sources, reduce the number of expensive high-resolution encoders used, and have the effect of outputting high-quality images.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the PLL control circuit, Fig. 2 is a sectional view of the recording device, Fig. 3 is a diagram showing the vicinity of the conveyor belt, Fig. 4 is a diagram showing the vicinity of the photosensitive drum, and Fig. 5 is a diagram showing the motor. FIG. 2 is a simplified block diagram of a speed control circuit. 53 is an oscillator, 54 is a drum frequency divider, 55 is a belt frequency divider, 56 is a photosensitive drum control section, and 57 is a belt control section.

Claims (2)

[Claims] (1) A recording apparatus having a plurality of drive sources, including a plurality of control means for controlling the speed of each of the plurality of drive sources, and a signal generation means for supplying a reference signal to the plurality of control means. A recording apparatus characterized in that the frequency of the reference signal is divided according to the accuracy of each of the plurality of control means. (2) The recording apparatus according to claim 1, wherein the plurality of drive sources control a rotating body for image formation and a member for conveying recording material.