JPH02202165A - Original scanning device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exposure device that illuminates an image on a document and guides the reflected light to a light receiving section such as an image sensor or a photosensitive drum.

(Prior Art) In general, in copying machines, image scanners, etc., an original placed on an original platen glass is illuminated by a light source and a mirror, and the reflected light is imaged and exposed on a light receiving section, which is the so-called 1: buff exposure. equipment has been adopted. As shown in FIG. 9 and FIG.
Two wires a and b are fixed to the movable body 109, and the rotational force of a drive source 111 is transmitted to the wires a and b via a gear group and a drive drum 112, and the movable body 109 moves. The bodies 109 and 110 run on rails 107 and 108.

During this traveling, the document P on the document platen glass 100 is illuminated by the light source 101 of the moving body 109, and the reflected light is reflected by the mirrors 102, 103, 104 of the moving body 1.09, and the imaging lens 105 Thereafter, the reflected light is converted into an electrical signal and output to an image processing section (not shown).

In this case, with respect to the traveling speed of the moving body 109, the moving body 11
0 by running at the speed of the station.

The optical path length from the document surface to the imaging lens 105 is always kept constant.

By the way, some of these types of devices require the reading to be interrupted and resumed at any time due to the convenience of the host computer connected to it while illuminating a single document. For example, when reading an image for computer input, In the scanner, when the buffer of the host computer connected to the light receiving unit 106 becomes full, illumination is temporarily interrupted, and reading of the original P is resumed when data processing on the host computer side is completed.

Generally, when rotating the drive source 111, slow-up and slow-down (gradually increasing or decreasing the rotational speed) are used to smoothly transition between a stopped state and a steady state. However, in the light receiving section 106 that employs a reading sensor such as COD, it is necessary to keep the reading time interval (accumulation time) of the l line constant, so reading is interrupted/resumed (hereinafter abbreviated as stop/start).
In this case, it is necessary to suddenly stop/rotate at the steady state rotation speed. That is, if the accumulation time is T and the number of pulses of the drive source 111 required to feed one line is n, then
At the time of stop/start, the driving source 111 is n/
It suddenly stops/rotates at a speed of T (pps).

(Problem to be Solved by the Invention) However, when the drive source 111 is suddenly stopped/rotated as described above, the bearings of the movable bodies 109 and 110 that receive the rails 107 and 108 are damaged (not shown). The rails 107 and 108 get stuck, and the moving object 110
At the left end (rail 107 side) and right end (rail 108 side), there is a difference in the time it takes from when a drive signal from the drive source 111 is applied until it actually starts moving. As a result, there is a problem in that the reflected light guided to the light receiving section 106 is disturbed, affecting the electrical signal output to the image processing section, and the image information finally obtained becomes incomplete. .

This invention is intended to solve the above-mentioned problems, and aims to improve the running stability of the exposure apparatus when it resumes running after stopping, by giving the exposure apparatus a degree of freedom in the horizontal plane. There is.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a moving body that illuminates a document while traveling along a pair of parallel rails and guides the reflected light to a light receiving section. The vehicle is equipped with a displacement means that allows the body to be displaced in a plane parallel to the running direction.

(Function) The effect of the present invention based on the above configuration is that since the movable body can be displaced in a plane parallel to the running direction, stick-slip does not occur even if the movable body suddenly starts running from a stopped state.

(Example) The present invention will be explained below based on the illustrated example. 3 and 4 show a schematic configuration of an image reading device to which the present invention is applied. That is, l is a light receiving section (reading sensor) made of a CCD or the like, and is arranged inside the main body 2 of the apparatus.

- A document placing glass 3 is provided on the upper surface of the blade device main body 2, and the document P placed on the document am glass 3 is illuminated by the exposure device A, and the reflected light is guided onto the reading sensor 1. It has become.

The exposure apparatus atA is composed of a wire-driven lamp unit (moving body) 5, and a mirror unit (moving body) 6. Note that 7 is an imaging lens. The lamp unit 5 includes an illumination lamp L that illuminates the original P, and a first mirror Ml that reflects the image reflected light from the surface of the original P illuminated by the illumination lamp L to the mirror unit 6 side.

On the other hand, the mirror unit 6 includes a second mirror that returns the image light reflected by the first mirror Ml toward the reading sensor 1. Third mirrors M2 and M3 are provided.

The lamp unit 5 and the mirror unit 6 are supported by a rail 8a and a flat rail 8b so as to be able to scan parallel to the optical axis while keeping the lamp unit 5 perpendicular to the optical axis of the lens 7.

Reference numeral 9 denotes a drive source for driving the lamp unit 5 and the mirror unit 6, and the rotation thereof is transmitted to the drive drum IO via a gear group. In general, this type of image reading device has a drive source 9 because position control and speed control are easy.
A pulse motor is often used as a drive drum.
a and 11b are wound. One end of each wire is fixed to the lamp unit 5 halfway, passes half a turn on pulleys 12a and 12b at both ends of the mirror unit 6, and is fixed to the main body. Also, the other end of the wire is connected to pulleys i2a and 12b.
It goes half way around J2 and is connected with a tension spring 13. Thereby, the mirror unit 6 travels at the speed of the collar of the lamp unit 5 based on the principle of a movable pulley, so that the optical path length is always kept constant over the entire travel region.

The lamp unit 5 and mirror unit 6 are usually
A home position sensor (not shown) sets the home position near the document illumination start position.

Figures 1 and 2 show the displacement means B provided in the mirror unit 6, in which 17 is a ring-shaped bearing;
A and 16b are holes into which the bearing 17 is inserted. One hole 1
6a is formed with a hole diameter that allows the bearing 17 to be fixed with an interference fit, and the other hole 16b has a dimension L< in the vertical direction relative to the running surface that is equal to the hole diameter of 16a, and is larger in the horizontal direction. It has an oblong hole shape. The depth of both 16a and 16b is equal to or slightly deeper than the length of the bearing 17.
18 is a bar for preventing the bearing 17 inserted into the mirror unit 6 from coming off from the mirror unit 6, and is fixed to the main body 16 and presses the end face of the bearing 7.

The other end of the lamp unit is supported at one point by rollers K on the flat rail 8b.

Therefore, the mirror unit 6 has a length corresponding to the long diameter of the oblong hole 18b.
It has a degree of freedom to swing in the horizontal plane (in the direction of the arrow in the figure). Therefore, when starting up, the bearing 17 of the mirror unit 6 is attached to the rail 8.
The force of trying to bite a is completely gone, and stick-slip no longer occurs.

FIG. 5 is an example of a processing block diagram of read image data of the image reading apparatus shown in FIG. 3. After the analog image signal from the reading sensor 6 is amplified by the amplifier 22,
0 image processing circuit 24 which is converted into a digital image signal by the A/D converter 23 and inputted to the image processing circuit 24
Then, the digital image signal is binarized according to instructions from the CPU 27. Note that the CPU 27 uses image processing parameters stored in advance in the ROM 28 to supply the threshold level for binarization and shading correction data to the image processing circuit. It also outputs a drive signal to a drive circuit 29 that drives the drive source 9 . Image processing circuit 2
The output from 4 is branched into two, one is directly connected to the selector 26, and the other is connected to the subsequent selector 26 via the buffer memory 25 in accordance with instructions from the CPU 27.

An image sensor such as a COD that constitutes the light receiving section 6 normally operates under a clock that is output at regular intervals. Two cycles are required to process one line of image data, and as shown in the timing chart in Figure 6, the image is read in the first cycle, and the read data is transferred in the next cycle. . In the same figure, Hsyn
c is a read synchronization signal issued every accumulation time T (asec) of the image sensor, and SPM is a pulse motor drive signal issued in synchronization with Hsync.0 In this embodiment, by giving 4 pulses to the pulse motor, l
We are sending lives worth.

Normally, the selector 26 directly connects the image processing circuit 24.
The data on the line that is being read at the time the host computer issues the reading interruption command will not be accepted in the next cycle, and will be transferred after reading resumes. be done. Therefore, when reading is resumed, the selector 26 is connected to the line buffer 25, and the image of the last line read before the interruption is first transferred, and then the selector 26 is switched to the normal state.

In the image reading device configured as described above, when a read start command is issued from the host computer, a drive pulse synchronized with the read synchronization signal is given to the drive source 9, and the exposure device A starts running and starts reading. Image data is sent to the host computer.

The host computer processes the image signals sent to it, but if the buffer becomes full and the image signals cannot be processed, a reading interrupt command is sent to the reading device. When the reading device receives this signal, it temporarily stops the rotation of the drive source 9 and the transmission of the image signal, and enters a standby state. When the host computer issues a command to resume reading, reading is resumed from this position.

7 and 8 show other embodiments of the displacement means B. In FIG. 0, 27 is a bearing made of a material with excellent wear resistance, such as polyacetal or nylon,
The fitting hole 27a has an oval shape. Its outer shape has the same shape as the hole 28 for mounting the main body 16, and the bearing 27
It is designed to be attached with an interference fit, with the long axis always in the horizontal direction.

Note that the pair of bearings 29 may be made of the same material and have a round hole shape, or the mirror unit 6
Since the read image does not change even if the bearing 29 moves in a horizontal plane in a direction perpendicular to the running direction, the bearing 29 may be mounted in the same direction as above.

Furthermore, if there are no problems with strength or thermal changes, it is conceivable to integrate the bearings 29, 27 and the main body 16 and make them from the above-mentioned materials.

In the above embodiment, a case has been described in which the displacement means B is provided on the mirror unit 6 side, but since stick-slip of the lamp unit 5 may have an effect, this embodiment also applies to the bearing of the lamp unit 5. The same structure as described in the example may be adopted.Furthermore, it goes without saying that the present invention may be applied not only to an image reading device but also to a copying machine that guides reflected light to a photoreceptor, such as an electrophotographic method. .

(Effects of the Invention) Since the present invention is configured as described above, running defects that occur when the exposure apparatus is once stopped and then run again are eliminated. Therefore, when this invention is used in an image reading device or a copying machine, the output signal from the light receiving section is exposed halfway! This has an excellent effect in that it does not change even if there is a stop/start operation of am, and the image information finally obtained is not affected.

[Brief explanation of the drawing]

Figures 1 to $8 show embodiments of the present invention, Figures 1 and 7 are side views of the displacement means, Figures 2 and 8 are plan sectional views of the displacement means, and Figure 3 is an image. FIG. 4 is a side sectional view of the image reading device shown in FIG. 3; FIG. m5 is a block diagram showing the main circuit configuration of the image reading device shown in FIG. 3; FIG. 3 is a timing chart showing the operation of the image reading device, and FIG. 9 and FIG. 1θ are a plan sectional view and a side sectional view showing the conventional image reading device. Explanation of symbols l... Light receiving section (reading sensor) 5.6... Moving object (lamp unit, mirror unit)
g) 8a, 8b...Rail 18b...Elongated hole 17.2
7... Bearing 28... Hole A... Exposure device
B...Displacement means P...Manuscript

Claims (2)

[Claims] (1) A moving body is provided that illuminates the original while traveling along a pair of parallel rails and guides the reflected light to the light receiving section, and the movable body can be displaced in a plane parallel to the traveling direction. An exposure apparatus characterized by being provided with a displacement means. (2) The displacement means comprises a bearing that fits at least one of the rails, and an elongated hole that supports the bearing slidably in a plane parallel to the running direction. Exposure equipment. (3) The displacement means comprises a bearing that holds at least one rail so that it can slide in a plane parallel to the running direction, and a hole that fits and fixes the bearing. exposure equipment.