JPH05191574A - Method for reading charge coupling element - Google Patents

Abstract

PURPOSE:To attain the clear picture reading by generating each pulse signal and timing where the terminal in the main and sub scanning directions are to be discriminated and turning off a start signal at the end of the reading. CONSTITUTION:An amplifier/sample holder 16 amplifies the output data from a CCD 15 by a holder 16. The output data is read from the CCD15 at the sample-and-hold timing. An A/D conversion section 17 A/D converts the output from the holder 16 at the timing of A/D conversion. Thus, a signal is turned on when the reading starts, each pulse and timing for the line in the main scanning direction is successively generated, each pulse and timing whose terminal for the prescribed line is to be discriminated is generated, and each pulse and timing to discriminate the terminal in the sub scanning direction is generated. By turning off the start signal at the end of the reading, the stored data of excess picture reading is discharged to realize the clear picture reading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read control method for a charge-coupled device used in a copying machine or the like.

[0002]

2. Description of the Related Art A charge-coupled device used in a conventional copying machine or the like is configured to continuously read data.

The situation of image storage by a conventional reading method used in an apparatus for reading an image while scanning a charge-coupled device (hereinafter referred to as CCD) in which light receiving elements are arranged in the main scanning direction in the sub-scanning direction will be described. FIG. 7 shows the control of the CCD, and FIG. 8 shows it.

As shown in FIG. 7, the image in which the shaded area is accumulated is not the intended image but the image one line before and one line after, and turbidity occurs in the sub-scanning direction.

[0005]

In the conventional charge-coupled device described above, data can be continuously read, but it is possible to select specific data by removing unnecessary portions. However, there is a problem in that the unnecessary image is read line by line in the sub-scanning direction and the image becomes turbid.

The present invention provides a charge-coupled device reading control method capable of reading a clear image by discarding accumulated data of unnecessary image reading.

[0007]

According to the present invention, when reading is started, a start signal is set to ON, pulses and timings for a predetermined line in the main scanning direction are sequentially generated, and a predetermined line in the main scanning direction is generated. Each pulse until the end of a predetermined line in the main scanning direction is determined, each pulse and timing are generated, the end in the sub-scanning direction is determined, and each pulse is generated until the end in the sub-scanning direction is determined. And a charge-coupled device read control method for generating timing and turning off the start signal when the read is complete.

[0008]

In the read control method for the charge-coupled device of the present invention,
When reading is started, the start signal is set to ON, each pulse and timing for a predetermined line in the main scanning direction are sequentially generated, the end of the predetermined line in the main scanning direction is determined, and the predetermined line in the main scanning direction is determined. Each pulse and timing are generated until the end of the minute is determined, the end in the sub-scanning direction is determined, each pulse and timing are generated until the end in the sub-scanning direction is determined, and when reading is completed, the -Turn off the signal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a charge-coupled device (hereinafter referred to as CCD) reading control method of the present invention will be described below with reference to the drawings.

FIG. 1 is a flow chart showing an embodiment of a CCD reading control method of the present invention.

FIG. 2 is a CC to which the control method of FIG. 1 is applied.
It is a block diagram which shows the structure of one Example of the reading control apparatus of D (henceforth a control apparatus).

The control device of FIG. 2 has a timing generation circuit 1
1, drivers 12, 1 connected to the timing generation circuit 11
3,14, CCD15 connected to each driver 12,13,14,
Amplifier / sample holder 16 connected to CCD 15 and analog / sample connected to amplifier / sample holder 16
It is composed of a digital (hereinafter referred to as A / D) converter 17.

The timing generating circuit 11 of FIG. 2 for carrying out the control method of the present invention will now be described with reference to the flowchart of FIG.
The operation of will be described.

First, when the reading of the optical system is started, the star
Signal is set to ON (step S1), pulses and timing for one line in the main scanning direction are sequentially generated (step S2), and the end of one line in the main scanning direction is determined (step). S3), until the end of one line in the main scanning direction is determined, the above step S2 is executed to generate each pulse and timing, and the end in the sub scanning direction is determined (steps S4 and S5), and the sub scanning direction is determined. The above steps S2 and S3 are executed until the end of the above is determined to generate each pulse and timing, and when the reading of the optical system is completed, the start signal is turned off.

Next, referring to the flow chart of FIG.
The operation of the amplifier / sample holder 16 of FIG. 2 will be described.

First, the output data from the CCD 15 is amplified by the amplifier / sample holder 16 (step S7), and the output data from the CCD 15 is fetched at the sample hold timing (steps S8 and S9). Amplifier / sample holder 16 at A / D conversion timing by A / D converter 17
Output from the A / D converter (steps S10, S1)
1).

The situation of image storage and the control of the CCD by the control method of the present invention will be described with reference to FIGS. 4 and 5, respectively.

As shown in FIG. 4, in the control method of the present invention, the area of the shaded area, which is unnecessary image storage, is smaller than that of the above-described conventional reading control device (see FIG. 7), and the vicinity of the target image is obtained. Only the image is stored.

Control of the CCD according to the control method of the present invention will be described with reference to the timing chart of FIG.

As shown in FIG. 5, image reading of n (integer of n ≧ 1) lines is started, and after a lapse of time t ₁ , unnecessary images of n−1 lines are included in the images accumulated so far. Since those are the images, those images are discarded.

More specifically, as control of the CCD, after a time t ₁ , a shift pulse is issued to transfer the image accumulated in the light receiving element to the shift register, and the light receiving element is cleared (empty) to n. Start line image accumulation from 0.

Furthermore, since the image accumulated for the time t ₁ remains in the shift register as it is, a clock pulse is issued to empty the shift register.

In order to efficiently perform the above-mentioned blank reading, it is also necessary to discard unnecessary images of n lines generated in the reading time of the latter half of n-1 lines, and the processing during this time t is also performed. Do it all at once. Furthermore, the clock pulse is made faster by using the shift register twice in the processing of one line. Further, the light quantity of the light source is increased by shortening the image accumulation time.

With respect to the setting of the times t ₁ and t ₂ , the time (t ₁ = t / 2, t ₂ = t / 2) which is ½ of the scanning time t of one line is set for the turbidity of the image. This is ideal, but since the image storage time will be lost, the determination is made based on the level at which the image becomes cloudy and the balance of the image storage amount (including measures to increase the light amount).

FIG. 6 shows an example of the construction of a copying machine to which the control device of FIG. 2 is applied.

The copying machine 18 shown in FIG. 6 is provided with a document placing table 19 made of hard transparent glass on the upper end thereof.

A document (not shown) placed on the document table 19 is illuminated by the lamp unit 20, and the reflected light from the document passes through the mirrors 21, 22, 23 and the lens unit 24 to the CCD sensor. It is guided to the light receiving surface of 25 and taken in as an electric machine signal.

The lamp unit 20, the mirror 21, the CCD
A scanner is composed of the sensor 25 and the like. The image data captured by the CCD sensor 25 is processed by an image processing unit (not shown).
After that, it is sent to the laser driver unit 26 and is output as laser light (laser output light), and an electrostatic latent image pattern is formed on the photosensitive drum 29 rotatable in the arrow B direction via the mirrors 27 and 28. Photosensitive drum rotatable in the direction of arrow B
A charging charger 30 that uniformly charges the surface of the photosensitive drum 29 prior to exposure is provided in the rotation region of 29, and an electrostatic latent image is formed on the exposed portion by the laser output light described above. Further, on the downstream side of the charger 30, the black developing tank 3
1, a developing device having a yellow developing tank 32, a magenta developing tank 33, and a cyan developing tank 34, a transfer belt 35, a cleaning unit 36, and a charge eliminating lamp 37 are arranged in this order.
The developing tanks 31 to 34 of the developing device store the toner of the corresponding color.

In the above arrangement, color copying (three-color color copying) is performed by the following operation procedure.

When the charging charger 30 uniformly charges the surface of the photosensitive drum 29, the first scanning is performed by the scanner described above. The image data (R, G, B) taken in by the CCD sensor 25 passes through the image processing section to generate yellow data, which is output as laser light by the laser driver unit 26 to expose the surface of the photosensitive drum 29 for exposure. An electrostatic latent image of yellow is formed on the image area, and yellow toner is supplied from the yellow developing tank 32 to the electrostatic latent image of the image area to form a toner image of the same color.

Then, the toner image circulates in the direction of arrow B and is partially transferred onto the transfer belt 35 which is pressed against the surface of the photosensitive drum 29. At this time, a part of the toner that does not contribute to the transfer remains on the surface of the photoconductor drum 29, but the cleaning unit 36 scrapes off the remaining toner. Next, the static elimination lamp 37 eliminates residual electrification on the surface of the photosensitive drum 29.

When the above process is completed, the charging charger 30 charges the surface of the photosensitive drum 29 uniformly again,
The data from the original obtained by the second scan is exposed by the laser beam through the image processing unit, and a magenta electrostatic latent image is formed. Similarly, magenta toner is supplied to the electrostatic latent image from the magenta developing tank 33 to form a toner image of the same color, and the formed toner image is transferred to the transfer belt 35 to perform image superposition. After that, when the same processing as above is performed, the charging charger 30 charges the surface of the photoconductor drum 29 uniformly again, and in the same manner, cyan toner is supplied from the cyan developing tank 34 to the photoconductor drum 29 and the same color is obtained. A toner image is formed. Then, this toner image is transferred to the transfer belt 35, and final image superposition is performed.
After that, the toner image on the transfer belt 35 on which the images are superimposed is transferred to the copy sheet, passes through the fixing unit 38, and is then ejected outside the apparatus by the ejection roller 39.

The above-described process is a process in three-color, and in the case of a four-color process, black processing is further added to the above-described process. Also,
Black-and-white copying is performed by supplying black toner to the electrostatic latent image on the photosensitive drum 29 from the black developing tank 31 and transferring the supplied toner image to a copy sheet via the transfer belt 35.

[0034]

According to the charge-coupled device reading control method of the present invention, the start signal is set to ON when reading is started, pulses and timings for a predetermined line in the main scanning direction are sequentially generated, and the main scanning is performed. The end of a predetermined line in the main scanning direction is determined, each pulse and timing are generated until the end of the predetermined line in the main scanning direction is determined, the end in the sub-scanning direction is determined, and the end in the sub-scanning direction is determined. Until the end of reading, the start signal is turned off so that clear image reading can be realized by discarding the accumulated data of unnecessary image reading.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining an embodiment of a read control method for a charge-coupled device according to the present invention.

2 is a block diagram showing the configuration of an embodiment of a charge-coupled device read control device to which the read control method of FIG. 1 is applied.

FIG. 3 is a flowchart for explaining the operation of the amplifier / sample holder and the A / D converter of FIG.

FIG. 4 is an explanatory diagram of a situation of image accumulation by the reading control device of FIG.

5 is an explanatory diagram of a CCD control method by the reading control device of FIG.

6 is a block diagram showing a configuration example of a copying machine to which the control device of FIG. 2 is applied.

FIG. 7 is an explanatory diagram of a situation of image storage by a conventional copying machine.

FIG. 8 is an explanatory diagram of a CCD control method by a conventional copying machine.

[Explanation of symbols]

S1 Start signal ON setting stage S2 Main line scanning line pulse and timing generation stage S3 Main scanning direction one line end determination stage S4, S5 Sub-scanning end determination stage S6 Start signal OFF setting stage 11 Timing generation circuit 12 to 14 Driver 15 CCD 16 Amplifier / sample holder 17 A / D converter

Claims (1)

[Claims] 1. When reading is started, a start signal is set to ON, each pulse and timing for a predetermined line in the main scanning direction are sequentially generated, and the end of the predetermined line for the main scanning direction is determined. , The pulses and the timing are generated until the end of the predetermined line in the main scanning direction is determined, the end in the sub-scanning direction is determined, and the pulses are output until the end in the sub-scanning direction is determined. And the timing is generated,
A method for controlling the reading of a charge-coupled device, wherein the start signal is turned off when the reading is completed.