JPH06309449A - Scanner - Google Patents

Abstract

PURPOSE:To shorten the total time for reading and to stabilize light quantity during the period of reading by detecting the opening of an original cover and then starting the impression of voltage to a light source. CONSTITUTION:A control circuit turns on a power supply in co-operation with peripheral devices and moves the positions of a fluorescent lamp 5 and an optical unit 7 to respective original read starting positions. A person intending to use a scanner opens the original cover 2 at the time of setting up an original. At the time, light beams A, B in a room are reflected on the rear surface of the cover 2 and a part of the reflected light arrives at a CCD 10. The output of the CCD 10 is increased as compared with a case setting the cover 2 on the surface of a glass table 4. The control circuit detects the increment of the CCD output and impresses filament preheating voltage to the lamp 5. Then, the positions of the lamp 5 and the unit 7 are moved to respective white balance sheet reading positions. Then, a high voltage is impressed to turn on the lamp 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner using a one-dimensional CCD sensor.

[0002]

2. Description of the Related Art In recent years, a scanner has been widely used as a means for inputting a document or graphic data into a computer, or as an input means for a digital copying machine or a facsimile.

The scanner irradiates a document surface to be read with strong light from a light source, and reflects light from the document through an optical system.
Form an image on the image sensor. The image sensor photoelectrically converts each pixel to a voltage level proportional to the intensity of reflected light, that is, the lightness and darkness of a document to read an image. Amplify this and AD
It is transferred as digital data to the host system by conversion.

Generally, an image sensor uses a one-dimensional CCD sensor in which pixels are arranged on one line, and image information can be read by scanning a document by a mechanical section.

FIG. 2 is a block diagram of a CCD sensor used in a scanner. S ₁ , S ₂ , ..., _SN are light receiving parts (photodiodes), AS ₁ , AS ₂ , ..., AS
_N is an analog shift register (CCD) for shifting out the analog output of the light receiving unit, TGATE is a transfer gate for transferring the analog output of the light receiving unit to the analog shift register, and OB is an output buffer. Also,
φ _T is a transfer pulse, φ ₁ and φ ₂ are shift register transfer clocks, φ _R is a reset clock, and VOUT is a CCD output.

The voltages generated at the light receiving portions S ₁ , S ₂ , ..., _SN are transferred to the analog shift register in synchronization with the transfer pulse φ _T , and the transfer clocks φ ₁ , φ ₂ are transferred. From the output end of the shift register
It is output for each pixel.

FIG. 6 shows a general structure of a scanner.

The scanner comprises a glass table 2 on which an original 3 is placed, an original holder 2 for pressing the original 3, a white balance sheet 6 as a reference for CCD output, a light source 5 located below the white balance sheet 6, an optical unit 7, and a cabinet 1. To have. The optical unit 7 includes a mirror 8, a lens 9 and a CCD.
10 and 10.

The optical unit 7 stands by at the position for reading the white balance sheet shown in FIG. 8 and waits for the start of scanning.

When the scan is started, the optical unit 7
Is moved by a feeding device (not shown) in the direction indicated by arrow A in the figure.

At the time of scanning, the light emitted from the light source 5 passes through the glass table 4 and illuminates the original 3. Manuscript 3
The light reflected by is again transmitted through the glass table 4 and reflected by the mirror 8. The light reflected by the mirror 8 is condensed by the lens 9 and applied to the light receiving surface of the CCD sensor 10.

FIG. 4 is a circuit block diagram of a conventional scanner. The scanner receives the drive signals φ ₁ , φ ₂ , φ _R , and φ _T from the control circuit 47, and outputs VOU which is a CCD output.
CCD sensor 41 that outputs T and CCD output VOUT
A / D converter 42 for receiving and converting the signal into a digital signal, and terminals R0 ₊ , R0 ₋ , L for receiving the lighting voltage from the control circuit 47.
0 _+, L0 _- a light source 5 with, as a reference of the CCD output, CCD when reading the white balance sheet
Output of a white level memory 44 for storing an output, a counter 45 for generating an address for the white level memory 44, a NAND circuit 43 for generating a read / write signal R / W of the white level memory 44, and an AD converter 42. D0,
D1, ... D7 are output from the white level memory 44 MO0, M
It is composed of a ROM 46 which is normalized by O1, ... MO7.

Next, the reading process executed by the control circuit 47 in cooperation with peripheral devices will be described with reference to the flowchart of FIG. The optical unit 7 stands by at the position for reading the white balance sheet shown in FIG.

First, in step S101, the power is turned on.

In step S102, it is determined whether or not an instruction to start scanning a document has been input via an instruction means (not shown). Until input, step S1
The determination is repeated at 02, and if it is determined that the input is made, the process proceeds to the next step.

Next, in step S103, L0 ₊
A filament preheat voltage (about 6-8V) is applied between L0 ₋ and L0 _{− and} between R0 ₊ and R0 ₋ .

In step S104, it is determined whether 3 seconds have elapsed. Step S104 until 3 seconds elapse
The determination is repeated in step 3, and if it is determined that 3 seconds have passed, the process proceeds to the next step. After 3 seconds, the temperature of the filament of the fluorescent lamp becomes about 1000 ° C.

Next, in step S105, L0 _-
When R0 _- high pressure was added in about 100V or more between the fluorescent lamp 5
Light up.

Next, in step S106, the white balance signal WB = '1' is sent from the control circuit 47. The output VOUT of the CCD sensor 41 that has read the white white balance sheet 6 is converted to the AD converter 4
N 8-bit data (D0, D)
1, ... D7) is written to the white level memory 44.

The counter 45 transfers a transfer pulse φ to the CCD.
It is reset by the inverted signal of _T and counts up with φ _R. Addresses A0, A1, ... A of the output of the counter 45
M is the address of the white level memory 44,

[0021]

[Equation 1]

It is

Outputs of AD converter D0, D1, ...
・ D7 is the brightest of the fluorescent lamp and D0, D1, ・ when the CCD is reading the white balance sheet.
..Adjusted so that D7 = '1'. When the CCD output is digitally converted while there is no light, D0, D1, ...
..D7 = "0".

Next, in step S107, the white balance signal WB = '0' is transmitted from the control circuit 47. The white level memory 44 is in the read mode,
Outputs the white balance sheet read data.

Next, in step S108, the optical unit 7 and the fluorescent lamp 5 in FIG. 8 move to the right and start scanning the original.

DOUT0 and DOU of the ROM 46 at that time
T1, ... DOUT7 becomes the output of the scanner. The output of the ROM 46 at this time is

[0027]

[Equation 2]

In step 106,
The read data MO0, MO1, ... MO7 of the white balance sheet written in the white level memory 44 is normalized.

Next, in step 109, it is determined whether or not the scan is completed. If the scan has not ended, the process returns to step S108.

Next, in step 110, the filament voltage between L0 ₊ and L0 _−, between R0 ₊ and R0 ₋ and L
0 _- and R0 _- turns off the high pressure between extinguish the fluorescent lamp 5. The optical unit 7 is moved to the white balance sheet reading position which is the initial state, and the process returns to step S102.

[0031]

Fluorescent lamps are often used as the light source (lamp) of current scanners. The use of fluorescent lamps has the following two drawbacks.

1) It takes about 3 seconds to preheat the filament before lighting.

2) After lighting, the amount of light gradually changes as the temperature of the fluorescent lamp rises.

1) will be described. To turn on the fluorescent lamp, first, a voltage of about 6 to 8 V is applied to both ends (between L0 ₊ and L0 _{− and} between R0 ₊ and R0 ₋ ) of the filaments 52 and 53 shown in FIG. Then, after the filament reaches a high temperature of about 1000 ° C. in about 3 seconds, a high voltage of about 100 V or more is applied between L0 ₋ and R0 ₋ to turn on the light. In other words, there is a loss of about 3 seconds before lighting.

2) will be described. As shown in FIG. 9, the light quantity of the fluorescent lamp greatly changes depending on the temperature, and especially at 30 ° C. or lower, the light quantity greatly changes. Therefore, when the fluorescent lamp is cold,
When the reading of the original is started, the reading output changes during the reading.

It is an object of the present invention to provide a scanner that overcomes the above-mentioned two drawbacks and that can shorten the total reading time and stabilize the light quantity during reading.

[0037]

[Means for Solving the Problems] In order to achieve the above object,
A scanner of the present invention is a scanner including an optical unit including a CCD sensor and a light source, and means for moving the optical unit to a document reading start position before starting scanning, and an output of the CCD sensor at the document reading start position. And a means for starting the supply of voltage to the light source in response to the detection of the increase in the document pressing force.

Further, it is desirable to provide a means for updating the white level memory until the scan start command is input after the light source is turned on.

Further, it is provided with means for turning off the light source after a lapse of a predetermined time after the end of scanning and means for updating the white level memory until the light source is turned off after the end of scanning within a predetermined time. When the scan start signal is received, the scan may be started immediately.

[0040]

According to the scanner having the above structure, the optical unit is moved to the original reading start position before the start of scanning. If the operator presses the document holder in order to read the document, the output of the CCD sensor increases. This allows
Detects that the document holder is raised. When the raising of the document pressing is detected, the supply of the voltage to the light source is started, whereby the loss time can be reduced and the total time for reading can be shortened.

When a means for updating the white level before the scan is provided, the white level memory is updated until the scan start command is input after the light source is turned on, and the white level memory is updated immediately before the scan. The white level with the amount of light is stored in the memory. This ensures the stability of the amount of light during reading.

In the case where the means for updating the white level after scanning and the means for extinguishing the light are provided, the white level memory is updated until the light source is turned off after the scanning is completed, and the scanning is performed within a predetermined time. When receiving the start signal, the scan can be started immediately.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the scanner according to the present invention will be described in detail below.

The scanner has a structure similar to that shown in FIG. 6, that is, a glass table 2 on which an original 3 is placed, an original holder 2 for holding the original 3, a white balance sheet 6 as a reference for CCD output, and a lower portion thereof. Light source 5, located at
And an optical unit 7.

In this embodiment, the positions of the fluorescent lamp 5 and the optical unit 7 in the standby state are moved from the white balance sheet reading position to the document reading start position, as shown in FIG. Further, one cycle of the CCD at this time is set longer than T _INT shown in FIG. In FIG. 3, T _INT = t × N + 10.

This is ^designated as T _INT ^SCAN, and T _INT in the standby state is _designated as T _INT ^STAND-BY .

Assuming that T _INT ^STAND-BY = 10 × T _INT ^SCAN , the sensitivity of the CCD at this time is T _INT = T
10 times more than when _INT ^SCAN .

In the standby state, as shown in FIG. 7, when a person who intends to use the scanner sets a document, the document holder 2 is always raised. At this time, the light A or B in the room
Is reflected on the back of the document holder 2 and a part of the light is reflected by the CCD 10.
To reach. The CCD output is higher than that when the document holder 2 is set on the surface of the glass table 4 with the chitin.

That is, in the state of FIG. 7, the control circuit 47 of FIG. 4 detects that the CCD output has increased, so that the person using the scanner can know the timing at which the document is set.

Next, the reading process in the embodiment executed by the control circuit 47 in cooperation with peripheral devices will be described with reference to the flowcharts of FIGS. 1a and 1b.

First, in step S1, the power is turned on.

Next, in step S2, the positions of the fluorescent lamp 5 and the optical unit 7 are moved to the document reading start position shown in FIG.

Next, in step S3, the CCD 1
_Let the cycle be the cycle T _INT ^STAND-BY in the standby state.

Next, in step S4, it is determined whether the CCD output has increased. Step S until increased
The determination is repeated in step 4, and if it is determined that the number has increased, the process proceeds to the next step.

Next, in step S5, L0 ₊ and L0
0 _- between and R0 ₊ and R0 _- adding filament preheating voltage (approximately 6～8V) between.

Next, in step S6, the positions of the fluorescent lamp 5 and the optical unit 7 are moved to the white balance sheet reading position shown in FIG.

Next, in step S7, it is determined whether or not 3 seconds have elapsed after the preheating voltage was applied to the filament. The determination is repeated in step S7 until 3 seconds have elapsed, and when it is determined that 3 seconds have elapsed, the process proceeds to the next step.

Next, in step S8, L0 _- and R
A high voltage of about 100 V or more is applied between 0 ₋ to turn on the fluorescent lamp 5.

Next, in step S9, the control circuit 4
7 sets the white balance signal WB to "1",
Further, the white balance sheet is read and the read result is written in the white level memory.

Next, in step S10, it is determined whether or not an instruction to start scanning a document is input via an instruction means (not shown). The determination is repeated in step S10 until the input is made. Control circuit 4 until input
7 repeats reading the white balance sheet and writing the read result in the white level memory.

In step S11, the control circuit 47 sets the white balance signal WB to "0". The white level memory 44 enters the read mode and outputs the white balance sheet read data.

Next, in step S12, the optical unit 7 and the fluorescent lamp 5 shown in FIG. 8 move to the right to start scanning the original and read the original.

Next, in step S13, it is determined whether or not the scan is completed. If the scan has not ended, the process returns to step S12.

Next, in step S14, the fluorescent lamp 5
Then, the position of the optical unit 7 is moved to the white balance sheet reading position shown in FIG.

Next, in step S15, the control circuit 47 sets the white balance signal WB to "1", reads the white balance sheet, and writes the read result in the white level memory.

Next, in step S16, it is determined whether or not 5 minutes have passed since the end of scanning. If 5 minutes have not elapsed, the process proceeds to step S17. If it is determined that 5 minutes have passed, the process proceeds to step S18.

Next, in step S17, it is determined whether or not an instruction to start scanning the original has been input via an instruction means (not shown). Until it is input, the process returns to step S16, and if it is determined that the input is made, step S1
Move to 1.

Next, in step S18, the control circuit 47 sets the white balance signal WB to "0".

Next, in step S19, the filament voltage between L0 ₊ and L0 _−, between R0 ₊ and R0 _−, and L
0 _- and R0 _- turns off the high pressure between extinguish the fluorescent lamp 5. Return to step S2.

The advantages of this embodiment are as follows: 1) Before the scan command is received, the filament preheating voltage application time of 3 seconds, which is the loss time of the conventional scanner, can be saved.

2) Set a normal document and set the host side application software (resolution, reading area,
(Brightness etc.) takes a long time, so the change in the light amount will be quite stable before the scan. Since the value of the white level memory is being refreshed during that time, the white level with the calm light quantity immediately before the scanning is stored in the white level memory during the scanning. This allows
It is possible to ensure the stability of the light amount during reading.

3) Normally, in a scanner, once it is used once, it is usual to scan a plurality of originals continuously, but in such a case, this embodiment takes 5 minutes after the scan is completed. Constantly refreshes the white level memory without turning off the fluorescent lamp, and immediately starts scanning when a scan command is received.

[0073]

As described above in detail, in the scanner of the present invention, the means for moving the optical unit to the original reading start position before the start of scanning and the original pressing force from the increase of the output of the CCD sensor at the original reading start position. Since the means for detecting the rise of the document and the means for starting the supply of the voltage to the light source in response to the detection of the raising of the document pressing are provided, the loss time can be reduced and the total reading time can be shortened. .

If a means for updating the white level memory is provided after the light source is turned on until the scan start command is input, a normal document is set and application software on the host side is set ( Since it takes time for the resolution, reading area, brightness, etc.), the change in the light amount will settle before the scan. During that time, the value of the white level memory is being refreshed, so
At the time of scanning, the white level with a calm light amount immediately before the scanning is stored in the white level memory. Thereby, it is possible to ensure the stability of the light amount during reading.

Further, it is provided with means for turning off the light source after a predetermined time has passed after the end of scanning and means for updating the white level memory until the light source is turned off after the end of scanning within a predetermined time. When the scanning can be started immediately when the scan start signal is received, it becomes possible to scan a plurality of originals continuously and at the white level immediately before each scan, and It is possible to shorten the total time and ensure the stability of the light amount during reading.

[Brief description of drawings]

FIG. 1a is a flowchart showing a reading process according to an embodiment.

1b is a continuation of the flowchart of FIG. 1a.

FIG. 2 is a circuit block diagram of a CCD sensor.

FIG. 3 is a time chart of signals for driving a CCD sensor.

FIG. 4 is a circuit block diagram of a scanner.

FIG. 5 is a structural diagram of a fluorescent lamp.

FIG. 6 is a configuration diagram of a scanner.

FIG. 7 is a configuration diagram of a scanner showing a document reading start position.

FIG. 8 is a configuration diagram of a scanner showing a white balance sheet reading position.

FIG. 9 is a graph showing the relationship between the temperature of a fluorescent lamp and the amount of light.

FIG. 10 is a flowchart showing a reading process in a conventional example.

[Explanation of symbols]

 1 Cabinet 2 Original Press 3 Original 4 Glass Table 5 Fluorescent Lamp 6 White Balance Sheet 7 Optical Unit 8 Mirror 9 Lens 10 CCD

Claims (3)

[Claims] 1. A scanner provided with an optical unit including a CCD sensor and a light source, a means for moving the optical unit to a document reading start position before the start of scanning, and an output of the CCD sensor at the document reading start position. A scanner comprising: means for detecting an increase in the document pressing force from the increase; and means for starting the supply of a voltage to the light source in response to the detection of the lifting of the document pressing force. 2. The scanner according to claim 1, further comprising means for updating the white level memory until the scan start command is input after the light source is turned on. 3. A means for turning off the light source after a lapse of a predetermined time after the end of scanning, and a means for updating the white level memory until the light source is turned off after the end of scanning within a predetermined time. When the scan start signal is received at
The scanner according to claim 1, wherein the scanner is configured to start scanning immediately.