JPS63192009A - Image output device - Google Patents

Abstract

PURPOSE:To obtain an image of high quality by measuring the interval of time between a scan start signal and an image write signal and moving a writing device in accordance with this time. CONSTITUTION:An integrated light emitting unit 24 consists of a semiconductor laser, a collimator lens, and a cylinder lens and is moved in parallel by a motor 22 and a power transmission mechanism 23. When a signal is sent from a scan start sensor 10 at intervals of a certain time and a signal is sent from a write detecting sensor 17, an operation processing part 20 measures the interval of time between the write detection signal and the scan start sensor signal with about 1mus resolution and converts it to distance data and sends the signal to a motor controller 21 to rotate the motor 22 by a required extent of movement. Thus, the deviation of registration of the leading end of the image is minimized to obtain the image of high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to image writing control of an image output device that scans an image signal onto an image forming body to form an image.

[Conventional technology]

An example in which a laser optical system is used to form an image by scanning an image signal on an image forming body will be explained with reference to FIGS. 5 and 6. Laser light emitted from a semiconductor laser l passes through a collimator lens 2 cylinder lens 3
The beam is shaped, focused, and imaged on the rotating polygon mirror 4, and the beam reflected by the rotating polygon mirror 4 has its imaging point corrected by the fθ lens 5, and passes through the cylinder lens 6 onto the photoreceptor 7. The light is focused as a spot. The beam reflected by the rotating polygon mirror 4 due to the rotation of the rotating polygon mirror 4 is
It is scanned in the axial direction of the photoreceptor drum 8, and the scanning line 9 is moved by the rotation of the photoreceptor drum 8, and a latent image is formed by the image signal with a constant scanning line interval. Each time the laser beam scans, light traverses the scan start sensor 10 and outputs a signal to synchronize with the image signal.

FIG. 4 shows an example of an image output device capable of forming color images using the laser optical system. Yellow, magenta, cyan, and
4&ll laser optical system for black color 12 a, 12
b, 12c, 12d, photoreceptors 13a, 13b,
13c, 13d and developing device 14a.

14b, 14cS14d are provided, and after a latent image corresponding to each color is formed on each photoreceptor by each laser optical system,
A toner image is formed by the developing device.

Then, while the paper fed from the cassette tray 15 passes through the paper feeding unit 11, the toner images on each photoreceptor are superimposed and transferred, forming a color image.
The image is fixed in the fixing device 16. At this time, the writing start sensor 17 outputs a signal to the optical system unit to output an image signal when the paper reaches a predetermined position.

[Problem that the invention seeks to solve]

Incidentally, in an image output device that scans a photoreceptor with a laser beam to form a plurality of images and superimposes them on a single sheet of paper, the positional accuracy (registration) of the superimposed images is important.

However, printers using conventional laser scanners have a problem in that when scanning with one beam, a maximum deviation of one line occurs even if the writing timing is adjusted. That is, as shown in Fig. 3, the signal from the scan start sensor is output at fixed time intervals T, but the signal from the write start detection sensor is output with a lag of 12 hours, so the signal from the scan start sensor is output immediately after the scan start signal. This is because when a write start signal is received, writing cannot be started until the next scan start signal is received.

For example, in a 400 ps + laser scanning system, it is approximately 64 μ
In addition, in a laser scanning system that can write at high speed with multiple beams, the deviation will be multiple times. For example, in the case of 2 beams at 400 ps t, the deviation will be about 130 μm, and other errors will be included on the paper. Therefore, there is a problem in that the deviation of the registration region becomes large and the image quality deteriorates.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image output device that can obtain high-quality images by minimizing the deviation of registration regions.

[Means for solving problems]

To this end, the image output device of the present invention is an image output device that scans an image signal onto an image forming body to form an image, and measures the time interval between a scan start signal and an image write signal, and forms an image according to the time. It is characterized by moving a writing device for writing on the body.

[Effect]

In the present invention, as shown in FIGS. 2 and 3, for example, a signal is sent from a scan start sensor at intervals of a predetermined time T+,
When a signal is sent from the write detection sensor, the time interval TI between the write detection signal and the signal from the scan start sensor is measured, converted to distance data, and the motor is rotated by the required amount of movement. As shown in the figure, the beam moves from the regular position to the position B, and on the photoreceptor 7 the beam moves from the position a to the position b by the amount of delay, which minimizes the deviation of the registration region. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the image output device of the present invention, and FIGS. 2 and 3 are diagrams for explaining the present invention in detail. In FIG. 6, 4 is a rotating polygon mirror; is an fθ lens, 6 is a cylinder lens, 7 is a photoreceptor, 10 is a scan start sensor, 17 is a write detection sensor, 20 is an arithmetic processing unit, 21 is a motor controller, 22 is a motor, 23 is a power transmission mechanism, and 24 is a light emitting unit. Indicates a unit (writing device).

The image output device of the present invention is applied to, for example, the laser optical system and system described in FIGS. 4 to 6, and the same parts in the figures are denoted by the same numbers and the description thereof will be omitted.

In FIG. 1, an integrated light emitting unit 24 is composed of a semiconductor laser, a collimator lens, and a cylinder lens, and the light emitting unit 24 can be moved in parallel by a motor 22 and a power transmission mechanism 23. The motor 22 is a pulse motor or a servo motor whose position can be controlled. When a signal is sent from the scan start sensor 10 at an interval of conduction time TI and a signal is sent from the write detection sensor 17 (FIG. 3), the arithmetic processing unit 20 calculates the time between the write start detection signal and the signal from the scan start sensor. After measuring the interval with a resolution of about 1 μs and measuring T8 time,
The arithmetic processing unit 20 converts T2 into distance data, sends a signal to the motor controller 21, and rotates the motor 22 by the required amount of movement.

For example, in the case of a laser optical system with 400 spi and 1 beam, there will be a maximum deviation of the writing start position of 64 μm, but T
64 x 400 when + is 500 μs and T8 is 400 μs
"A correction of 500-51 am is required. Then, the motor 22 is rotated by this correction amount, the power transmission mechanism 23 is driven, the light emitting unit (writing device) 24 is moved, and the beam is emitted as shown in FIG. is moved in the rotational direction of the photoreceptor 7. That is, when the light emitting unit 24 is at the regular position A, the laser beam is scanning the position a on the photoreceptor 7, and the motor 22 When the light emitting unit 24 is moved to the dotted line position B, the beam moves over the photoreceptor 7 by the same distance and scans the position b, which makes it possible to minimize the displacement of the registration rays. can.

The above effects can be summarized as shown in FIG. 3. In other words, in the color printer equipped with four laser optical systems shown in FIG. 4, the light emitting unit is moved during the next scan after the start of writing is detected, and the image is thinned out by one line and written from the next scan. Since the 1-line scan is thinned out for each of the 4 image write operations, it does not affect the registration shift. Also, if the T3 time becomes short and the motor etc. cannot respond, the 2-line scan time is reduced to the light emitting unit movement time. You can spend it.

Note that it goes without saying that the present invention is not limited to the embodiments described above and can be modified in various ways. For example, in the embodiments described above, a laser optical system is used, but an LED array may be used. In the printer used, the registration silane can be similarly corrected by moving the LED exposure unit.

In addition to writing devices that use exposure units, the present invention can also be applied to image output devices that use electrostatic methods that use hard electrodes or ion currents.

〔Effect of the invention〕

As explained above, according to the present invention, by measuring the time interval between the scanning start signal and the image writing signal and moving the writing device for writing on the image forming body according to the time, the resist at the leading edge of the image is It is possible to minimize the deviation of the laser run and obtain high-quality images.

In particular, in an image output device that scans a photoreceptor with a laser beam to form multiple images and superimposes them on a single sheet of paper, it is possible to minimize the deviation of the registration region of the superimposed images. , high quality images can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the image output device of the present invention, FIGS. 2 and 3 are diagrams for explaining the present invention in detail, and FIG. 4 is a diagram to which the image output device of the present invention is applied. The system configuration diagrams shown in FIGS. 5 and 6 are configuration diagrams of conventional laser optical systems. 1... Semiconductor laser, 2... Collimator lens,
3... Cylinder lens, 4... Rotating polygon mirror, 5...
... rθ lens, 6... cylinder lens, 7...
Photoreceptor, 8... Photoreceptor drum, 9... Scanning line, 10
...Scanning start sensor, 11...Paper feed unit, 1
2a-d...Laser optical system, 13a-d...Photoreceptor, 14a-d...Developer, 15...Cassette tray, 16...Fixer, 17...Writing detection sensor, 20... Arithmetic processing unit, 21... Motor controller, 22... Motor, 23... Power transmission mechanism, 24
...Light emitting unit (writing device). Applicant: Fuji Xerox Co., Ltd. Representative Patent Attorney Hiroki Shirai (2 others) No. 1N 12 Figure 4 Text Figure 3-1 (1

Claims (2)

[Claims] (1) In an image output device that scans an image signal onto an image forming body to form an image, writing is performed to measure the time interval between a scan start signal and an image writing signal and write on the image forming body according to the time interval. An image output device characterized by moving the device. (2) The image output device according to claim 1, wherein the writing device is a laser emitting unit.