JPH089258A - Image reader - Google Patents

Abstract

PURPOSE:To provide an image reader which can secure a sufficient quantity of light despite, a minute quantity of light which is incident on a light receiving part and also can transfer data at a high speed. CONSTITUTION:A PD-row RED1 receives the images on the same line by the scanning of a TD1 and transfers the acquired electric charge to a PD-row RED2. Then the RED2 receives the images according to the scanning of a scanner and integrates its acquired electric charge with the electric charge acquired at the RED1. Then a PD-row RED3 receives the images and integrates its acquired electric charge with the total electric charge acquired at the RED1 and the RED2. Thus the images are successively read and the integrated photoelectric charge is finally transferred to a CCD shift register 302 which distributes the received charge to the CCD shift registers CCD1, CCD2, CCD3 and CCD4 of four stages in the horizontal direction and every four pixels. Thus the integrated electric charge is horizontally transferred. Such scanning operations are also applied to BLUE and GREEN respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus having a plurality of photoelectric conversion element arrays for photoelectric conversion and photoelectric charge transfer.

[0002]

2. Description of the Related Art Conventionally, a CCD sensor has been used in a scanner section of an image reading apparatus, and photoelectric conversion of an image read by the CCD sensor and transfer of photoelectric charge are performed.

[0003]

However, according to the above-mentioned conventional example, for example, when the scanning speed of the scanner is increased, the amount of light per unit area incident on the opening of the photocell of the CCD sensor is reduced. The density of the output image decreased and the desired density could not be obtained.

[0004]

[Means for Solving the Problems]

1) According to the present invention, a light receiving portion in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a charge from the light receiving portion is output as an electric signal C
Solid-state image pickup means having a CD shift register and a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register, a scaling factor setting means for setting a scaling factor, and the scaling factor. A first determining unit that determines the number of stages of the light receiving unit of the solid-state imaging unit according to the scaling ratio set by the setting unit, and an electric charge accumulated in the stages of the number of stages determined by the first determining unit And a charge transfer means for transferring the charges to the transfer gate while sequentially accumulating the charges of the next adjacent stages.

2) According to the present invention, a light receiving section in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a CCD shift register for outputting electric charges from the light receiving section as an electric signal, Solid-state image pickup means having a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register, and temperature detecting means for detecting the temperature of the scanner portion,
A light quantity detecting means for detecting the light quantity of the document irradiation lamp, a temperature judging means for judging whether or not the temperature of the scanner section is rising based on the temperature detected by the temperature detecting means, and an affirmative judgment by the temperature judging means. If determined, the light amount determination means for determining whether or not the light amount has decreased based on the light amount detected by the light amount detection means, and, if a positive determination is made by the light amount determination means, detected by the light amount detection means Second determining means for determining the number of stages of the light receiving section of the solid-state image pickup means based on the amount of light, and charges accumulated in the stages having the number of stages determined by the second determining means,
Charge transfer means for transferring the charges to the transfer gate while sequentially accumulating the charges of the adjacent next stages.

3) According to the present invention, a light receiving section in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a CCD shift register for outputting electric charges from the light receiving section as an electric signal, A solid-state image pickup means having a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register, a density setting means for setting the density, and a density set by the density setting means. Accordingly, third determining means for determining the number of stages of the light receiving section of the solid-state imaging means,
Charge transfer means for transferring charges accumulated in the stages of the number of stages determined by the third determining means to the transfer gate while sequentially integrating the charges of the next adjacent stages. To do.

4) According to the present invention, a light receiving section in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a CCD shift register for outputting electric charges from the light receiving section as an electric signal, Solid-state image pickup means having a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register, time measuring means for measuring the continuous irradiation time of the document irradiation lamp, and the time measuring means. A time determination means for determining whether or not the time exceeds a predetermined reference time, and a light amount setting for setting the light amount of the original irradiation lamp based on the time measured when the time determination means makes a positive determination. Means and fourth determining means for determining the number of stages of the light receiving section of the solid-state image pickup means according to the light quantity set by the light quantity setting means. And a charge transfer unit that transfers the charges accumulated in the stages of the number of stages determined by the fourth determining unit to the transfer gate while sequentially integrating the charges of the next adjacent stages. Characterize.

5) In the invention described in any one of 1) to 4) above, an electric charge is transferred to the overflow drain arranged on the opposite side of the transfer gate with the light receiving section interposed therebetween, and the electric charge transfer means to the overflow drain. And a charge discharging unit that discharges the electric charge of a stage that is not controlled.

[0009]

[Action]

1) According to the present invention, the number of stages of the light receiving portion of the solid-state imaging means is determined by the first determining means according to the scaling ratio set by the scaling ratio setting means, and the charges accumulated in the stages having the determined number of stages. Are sequentially added to the charges of the next adjacent stages and transferred to the transfer gate by the charge transfer means.

2) In the present invention, based on the temperature detected by the temperature detecting means, it is judged by the temperature judging means whether or not the temperature of the scanner section is rising, and when the affirmative judgment is made, it is detected by the light amount detecting means. The light amount determination means determines whether or not the light amount has decreased based on the determined light amount, and when the determination is affirmative, the second determination means determines the number of stages of the light receiving section of the solid-state imaging means based on the light amount detected by the light amount detection means. The charges accumulated in the stages having the number of stages determined by are transferred to the transfer gate by the charge transfer means while being sequentially integrated with the charges of the adjacent next stages.

3) According to the present invention, the number of stages of the light receiving portion of the solid-state image pickup means is determined by the third determining means according to the concentration set by the concentration setting means, and the number of stages is stored in the determined number of stages. The charges are transferred to the transfer gate by the charge transfer means while sequentially accumulating the charges in the adjacent next stages.

4) According to the present invention, whether or not the time measured by the time measuring means exceeds the predetermined reference time is judged by the time judging means, and when the affirmative judgment is made, the original irradiation is performed based on the time measured. The light quantity of the lamp is set by the light quantity setting means, the number of stages of the light receiving section of the solid-state imaging means is decided by the fourth deciding means according to the set light quantity, and the charges accumulated in the stages of the decided number of stages are determined. , The charges are transferred to the transfer gate by the charge transfer means while being sequentially integrated with the charges of the next adjacent stages.

5) In the invention described in any one of 1) to 4) above, the electric charge of the stage to which the electric charge is not transferred by the electric charge transfer means is discharged to the overflow drain by the electric charge discharging means.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

<First Embodiment> FIG. 1 shows a first embodiment of the present invention. In FIG. 1, reference numeral 401 denotes an operation unit for starting copy and selecting various modes. 40
A temperature sensor 2 is arranged at an appropriate position of the scanner unit and detects the temperature of the scanner unit. 403
Is a light amount sensor, which is arranged around the document irradiation lamp 103 (FIG. 2) and detects the light amount of the document irradiation lamp 103. 405 is TDI (Time Delay and Integrate
d) A sensor that converts the reflected light from the document into an image signal. 404 is a CPU (central processing)
unit), and the temperature sensor 402 and the light amount sensor 40
The control unit 401 and the TDI sensor 405 are controlled via a common bus (com.bus) based on the information obtained from the data bus 3 through the data bus.

FIG. 2 shows the structure of the image reading apparatus according to this embodiment. In FIG. 2, 405 shows the same part as FIG. Reference numeral 101 denotes a document feeder (feeder) for feeding the documents to be copied one by one. Reference numeral 102 denotes a document table glass for placing a document. 10
Reference numeral 3 denotes a document irradiation lamp for illuminating a document. 10
Reference numeral 4 denotes a scanner, which scans a document surface to read the document. Reference numerals 105 to 107 are first to third reflection mirrors, and 108 is a lens for guiding the reflected light from the document to the TDI sensor 405. Based on the image signal obtained by the TDI sensor 405, a laser driver (not shown) drives a laser (not shown).

Reference numeral 121 is a polygon mirror which reflects the laser light in a desired direction. Polygon mirror 1
A latent image is formed on the photosensitive drum 122 by the laser light from the image forming device 21, and the formed latent image is developed by the developing device 123.

The copy sheets to be copied are conveyed from the first and second sheet stacking devices 124 and 125, and transferred and transferred.
An image is copied onto a copy sheet by the separation charger 126.

The copy sheet on which the image has been copied is conveyed to the left in FIG. 2 by the conveying roller 127 and discharged by the sheet discharging roller 128. Also, the switchback unit 1
The conveying direction is switched by 29, and the discharge roller 128
By reversing, the copy sheet is conveyed to the intermediate path 130. A function that enables double-sided copying of copy paper, and a switchback 129 before reaching the discharge roller 128.
By switching the transport direction to the intermediate path 130, multiple copying is enabled. 140 is a sorter,
This is to sort the copy paper.

FIG. 3 shows the structure of the TDI sensor 405 shown in FIG. The light receiving unit 201 of the TDI sensor 405 is a PD
(photo diode) columns are provided for each color m stages in the vertical direction of the figure. In the PD row of one stage, n photocells are arranged in the horizontal direction of the figure. The TDI sensor 405 is scanned in the vertical direction in the figure, and the obtained photoelectric charges are sequentially transferred in the vertical direction in the figure. The transferred charges reach the transfer gate 202, and the transfer gate 202 is opened and closed at a certain timing to transfer an image signal for each line to a CCD (charge coupled device) shift register 203. An image is converted into an electric signal by sequentially transferring this charge in the horizontal direction in the drawing.

FIG. 4 schematically shows the internal structure of the light receiving section 201 shown in FIG. To simplify the explanation, the transfer gate 202 shown in FIG. 2 is omitted. Light receiving unit 201
For R (RED), B (BLUE), and G (GREEN), there are three rows of PD columns (301, 303, 305) and four, respectively.
Stage CCD shift register (302, 304, 306)
Shall have.

When the TDI sensor 405 is scanned in the scanning direction shown in FIG. 4, first, the PD column RED1 receives an image on the same line and transfers the obtained charges to the PD column RED2. Then, according to the scanning of the scanner 104, the PD row R
The light is received by the ED2, and the charges obtained here are integrated with the previous charges. At this time, the PD column RED1 reads the next one line.

Next, the PD row RED3 receives light, and the charges obtained here are integrated with the total sum of the charges obtained in the PD rows RED1 and RED2. In this way, the photoelectric charges accumulated in the sequential reading are finally read by the CCD shift register 302.
5 and, as shown in FIG. 5, four pixels in the horizontal direction are set as one unit, and four stages of CCD shift registers CC are provided.
It is distributed to each stage of D1, CCD2, CCD3, and CCD4 and transferred in the horizontal direction.

Such scanning is performed for RED, BLUE, and GREEN, and a sufficient amount of light can be obtained even when the amount of light incident on the light receiving unit 201 is weak, and data can be transferred at a higher speed. You can

A conventional image reading apparatus is a scanner 10
In the system in which the image scaling ratio is changed by the scanning speed of 4, when the scanning speed is considerably high, the amount of light incident on each photocell of the PD row per unit time is reduced. However, in the case of a copying machine having the above-mentioned characteristics and having a variable magnification mechanism, the information indicating what the variable magnification is is the operation unit 40.
1 sent to CPU 404 via common bus, CP
U404 determines the optimum number of stages of the TDI stage (PD row), and the information of the determined number of stages is T.
It is sent to the DI sensor 405. For example, an intermediate value of the total number of TDI stages is set to a normal value, and control is performed such that the number of TDI stages is increased when the light amount is small depending on the reading conditions.

FIG. 6 is an explanatory diagram for explaining a method of actually switching the number of TDI stages. To simplify the description, only one of the three colors of RGB is shown, and T
The number of DI stages is 3 (actually, there are many TDI stages).

As shown in FIG. 6, the TDI sensor 405 has TDI stages 501, 506 and 511, and shift registers 502 and 507 are provided between the TDI stages 501, 506 and 511, respectively. The shift register 502 has three-phase transfer clocks 503, 50.
4, 505 are sequentially supplied, and the shift register 507 is sequentially supplied with three-phase transfer clocks 508, 509, 510. For example, by giving transfer clock 503-> transfer clock 504-> transfer clock 505,
Photoelectric charges are transferred in the vertical direction and the forward direction in the figure. A transfer gate 512 is arranged outside the final stage of the plurality of TDI stages, is driven by a clock 513, and transfers photoelectric charges accumulated in the plurality of stages to a CCD transfer register 514. On the other hand, the shift registers 502 and 507 are driven in reverse vertically. For example, by driving the transfer clock 505-> the transfer clock 504-> the transfer clock 503 in this order, unnecessary photoelectric charge is removed from the OFD (overflow drain) 51.
Can be thrown away in 5. In this way, photoelectric charges can be transferred reversibly in the reverse direction.

When reading an image, first, photoelectric conversion of the image is performed in the TDI stage 501, and an electric charge according to the amount of light entering each photocell is obtained. This charge is transferred to the TDI stage 5 through the shift register 502.
06. Next, the charges obtained in the TDI stage 506 are integrated with the charges transferred from the TDI stage 501, and further transferred to the next TDI stage via the shift register 507. The charges transferred to the final stage in this way are transferred to the transfer gate 5
When 12 is opened, it is transferred to the CCD transfer register 514, and from there, it is transferred in the horizontal direction.

If only one of the three stages is needed, the charge obtained in TDI stage 501 is
When the transfer clock 503 is not driven, for example, in the case of positive logic drive, by setting it to low, it is immediately discarded to the transfer gate 512 and is not transferred to the TDI stage 506. Next, the electric charge obtained in the TDI stage 506 is set in the state where the transfer clock 508 is not driven, and the shift register 502 is set to transfer clock 505-> transfer clock 504-> transfer clock 503, respectively. The charge is transferred to the TDI stage 501 by driving in the direction opposite to the normal direction, and is discharged to the OFD 515 from the TDI stage 501, and thus is not transferred to the TDI stage 511. As described above, only the photoelectric charges obtained in the TDI stage 511 are output from the CCD transfer register 514.

Next, a method of driving the shift register shown in FIG. 6 will be described with reference to FIGS. FIG. 8 shows an example of the timing of each shift register drive clock.

Three-phase shift registers 601, 602, 6
03 is in the normal state when the drive clock is low,
It is not driven until the drive clock goes high, and the barrier potential is lowered.

The shift register 601 has a shift register driving clock SH1 (see FIG. 8; the transfer clock 50 in FIG. 6).
3 and 508). The shift register 602 is a shift register drive clock SH2.
(See FIG. 8, corresponding to transfer clocks 504 and 509 in FIG. 6). The shift register 603 is driven by a shift register drive clock SH3 (see FIG. 8, which corresponds to the transfer clocks 505 and 510 in FIG. 6).

The charges obtained by the TDI stage 501 (506) are transferred to the shift register 601 at timing t1.
Only the electric current is driven into the "potential well" (see FIG. 7A). Then timing
At t2, the shift register 602 is further driven to move the charges in the horizontal right direction in FIG. 7 (see FIG. 7B). At timing t3, the shift register 601 returns to its original state, and the electric charge is further moved horizontally rightward in FIG. 7 by the shift register 603 driven instead (see FIG. 7C). Then, at timing t4, the only shift register to be driven is the shift register 603 (see FIG. 7D), and when the driving of the shift register 603 is released at timing t5, the charge is transferred to the next PD column 506. (51
1) is transferred (see FIG. 7E).

As described above, it is possible to transfer photoelectric charges between PD columns. However, each timing of the shift register driving clock is adjusted, and each shift register is rotated at a timing that is horizontally inverted with respect to the timing shown in FIG. , The photoelectric charge can be transferred in the opposite direction, that is, in the left horizontal direction in FIG. Photoelectric charges can be transferred in either forward or reverse directions depending on the configuration and drive timing of the shift register section.

As described above, by using the TDI sensor capable of transferring the photoelectric charges in the forward and reverse directions, unnecessary photoelectric charges can be discarded in the OFD 615, whereby the amount of photoelectric charges obtained from the TDI sensor can be reduced. Can be controlled.

In this example, the number of TDI stages is three, but in actuality, photoelectric charges can be obtained with even better accuracy by switching with a larger number of stages.

FIG. 9 is a flow chart showing an example of the control program stored in the ROM 404a shown in FIG.

At step S701, the initial state T
Set the number of DI stages. For example, the total number of TDI stages is 10, and the initial number of TDI stages is about 5 in the middle. Next, the scaling ratio input from the operation unit 401 is read in at step S702. In step S703, it is determined whether or not the scaling ratio is equal, and if a negative determination is made, it is determined in step S704 whether or not enlargement is performed. As a result of the determination, in the case of expansion, the optimum number of TDI stages is determined (the number of stages is increased) in step S705. On the other hand, in the case of reduction,
In step S706, the optimum number of TDI stages is determined (the number of stages is reduced).

Next, in step S707, it is determined whether the copy button has been pressed. When a negative determination is made, the process returns to step S702. If an affirmative decision is made, the optimum number of stages is set in step S708. At this time, according to the optimum number of stages, C
A switching signal is sent from the PU 404 to the TDI sensor 405 to control the photoelectric charge to be read. In step S709, copying is performed and the processing ends.

As described above, it is possible to correct the insufficient light amount of the read image caused by the change in the magnification.

<Embodiment 2> As a characteristic of the original irradiation lamp, it is well known that the amount of light emitted decreases as the temperature of the original irradiation lamp itself rises. For example, in a digital copying machine, if the irradiation time of the document irradiation lamp becomes long by increasing the number of copies, the light amount decreases due to the temperature rise of the document irradiation lamp itself, and therefore the image becomes thin. was there.

FIG. 10 is a flow chart showing an example of the control program stored in the ROM 404a shown in FIG.

In step S801, the initial number of TDI stages is set. In step S802, temperature data is read from the temperature sensor 402, and in step S803, the light amount data is read from the light amount sensor. Then, in step S804, it is determined based on the temperature data whether or not the temperature has risen since the previous reading. If an affirmative decision is made, it is decided at step S805 whether or not the light amount data has decreased. If an affirmative decision is made, the optimum number of stages is determined in step S806. Next, in step S807, it is determined whether or not the copy button is pressed, and if a positive determination is made, step S8
In step S08, the TDI sensor 405 is controlled so that the optimum number of stages is achieved, and in step S809, copying is performed, and the process ends.

As described above, since the present embodiment is configured as described above, even if the original irradiation lamp light amount may be reduced under the reading condition that the original irradiation lamp is irradiated for a long time, The optimal image can be obtained.

<Embodiment 3> In the copying machine, when the density of the output image is adjusted, conventionally, the light quantity of the document irradiation lamp is changed to adjust the density in an analog manner, or the read image data is read. In many cases, digital density adjustment that changes the data itself is performed by performing image processing such as preparing a density conversion table.

In this embodiment, the TDI from the CPU 404 is used.
By switching the number of TDI stages of the sensor, for example, the total number of TDI stages is set to 9 and the number of TDI stages in the case of normal density is set to 5. By increasing or decreasing the number of stages by the amount by which the density adjustment button is pressed in the light and shade direction, the original irradiation lamp light amount adjustment mechanism such as the above-mentioned analog density adjustment means or the density conversion function which is a digital density adjustment means The concentration can be adjusted without using a table. Further, by increasing the total number of stages and adjusting the light amount in the normal state, finer density adjustment can be performed.

FIG. 11 is a flow chart showing an example of the control program stored in the ROM 404a shown in FIG.

In step S901, the initial number of TDI stages is set. Assume that the total number of TDI stages is 9, and the initial stage number is 5. Next, the density data input from the operation unit 401 is read in step S902, and the number of TDI stages for the density data is determined in step S903.

In step S904, it is determined whether or not the copy button of the operation 401 has been pressed. If a positive determination is made, in step S905 the TDI previously determined is determined.
The number of stages is set in the same manner as in the first and second embodiments, copying is performed in step S906, and the process is completed.

In this way, the sensor itself can adjust the density of the image.

<Embodiment 4> An image used in a copying machine having a large number of copies per minute (CPM) and a long continuous copy time, such as a so-called center copy machine, in which the original irradiation lamp has a long irradiation time. In the reading device, it is conceivable that the temperature rise problem of the scanner unit may occur.

In particular, in an image reading apparatus capable of so-called "flow-reading" in which the scanner is fixed and the original is moved to read the image, since the scanner is fixed, the heat from the original irradiation lamp causes the original table or the table to move. It concentrates on only a part of the document holding plate and will be heated abnormally.

Irradiation of unillustrated originals is performed so that the temperature of the original irradiation lamp 103 does not become a dangerous state as described above according to the number of originals obtained by the original number detecting means (not shown) arranged in the original feeding device 101. An appropriate light amount of the document irradiation lamp is determined in advance by the lamp light amount adjustment circuit, and the optimum number of TDI stages is switched (increased) according to the determined light amount.

FIG. 12 is a flow chart showing an example of the control program stored in the ROM 404a shown in FIG.

In step S1001, the initial number of TDI stages and the light amount of the original irradiation lamp are set. Then, in step S1002, the number of originals obtained by the original number detecting means is read. Also, step S1003
At, the number of copies input from the operation unit 401 is read. Next, in step S1004, a determination is made as to whether or not the reading mode for performing "flow reading" of the original has been set.
Judge from the information input from. If the result of determination is that it is the flow-reading mode, in step S1005 the time for which the document irradiation lamp is irradiated is estimated from the number of documents, the number of copies, and other conditions. In step S1006, it is determined from the irradiation time of the document irradiation lamp 103 whether this is too long. If an affirmative decision is made, in step S1007, the optimum value of the original irradiation lamp light quantity is determined, and along with this, step S10.
At 08, the optimum number of TDI stages is determined. After this, in step S1009, it is determined whether or not the copy button is pressed, and if a positive determination is made, step S1009.
At 1010, the optimum number of TDI stages is set. In step S1011, a drive circuit (not shown) that drives the document irradiation lamp 103 is controlled so that the light is emitted with an optimum lamp light amount, and copying is performed in step S1012.

[0056]

As described above, according to the present invention,
With the configuration as described above, a desired density can be obtained even if the reading conditions change.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the structure of the image reading apparatus according to the first embodiment.

FIG. 3 is a schematic diagram showing a configuration of a TDI sensor 405 shown in FIG.

4 is a schematic diagram showing an internal configuration of a light receiving unit 201 shown in FIG.

FIG. 5 is an explanatory diagram for explaining a method of distributing photoelectric charges to a CCD shift register.

FIG. 6 is an explanatory diagram for explaining a method of actually switching the number of TDI stages.

7 is an explanatory diagram illustrating a driving method of the shift register illustrated in FIG.

FIG. 8 is a timing chart showing an example of the timing of each shift register drive clock.

9 is a flowchart showing an example of a control program stored in a ROM 404a shown in FIG.

FIG. 10 is a ROM 404a shown in FIG. 1 in the second embodiment.
3 is a flowchart showing an example of a control program stored in the.

FIG. 11 is a ROM 404a shown in FIG. 1 in the third embodiment.
3 is a flowchart showing an example of a control program stored in the.

FIG. 12 is a ROM 404a shown in FIG. 1 in the fourth embodiment.
3 is a flowchart showing an example of a control program stored in the.

[Explanation of symbols]

 401 Operation unit 402 Temperature sensor 403 Light intensity sensor 404 CPU 404a ROM 405 TDI sensor

Claims (5)

[Claims] 1. A light-receiving portion in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a CC for outputting electric charge from the light-receiving portion as an electric signal.
A solid-state image pickup means having a D shift register and a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register; a magnification change setting means for setting a magnification change; A first determining unit that determines the number of stages of the light receiving unit of the solid-state image capturing unit according to the scaling ratio set by the setting unit, and an electric charge accumulated in the stages having the number of stages determined by the first determining unit. And an electric charge transfer means for transferring the electric charges to the transfer gate while sequentially accumulating the electric charges of the next adjacent stages. 2. A light receiving section in which a plurality of stages having a plurality of photoelectric conversion elements in a horizontal direction are arranged in a vertical direction, and a CC which outputs electric charges from the light receiving section as an electric signal.
A solid-state image pickup unit having a D shift register and a transfer gate for controlling the transfer timing of charges from the light receiving unit to the CCD shift register; temperature detecting unit for detecting the temperature of the scanner unit; A light amount detecting means for detecting the light amount, a temperature determining means for determining whether or not the temperature of the scanner unit is rising based on the temperature detected by the temperature detecting means, and a positive determination by the temperature determining means A light amount determination means for determining whether or not the light amount has decreased based on the light amount detected by the light amount detection means; and, if an affirmative determination is made by the light amount determination means, the light amount determination means based on the light amount detected by the light amount detection means. Second determining means for determining the number of stages of the light receiving portion of the solid-state image pickup means, and a stage number of stages determined by the second determining means. Image reading apparatus characterized by comprising a charge transfer means for transferring charges accumulated in the di, the transfer gate while sequentially accumulated on the charge of each next adjacent stage. 3. A light receiving section, in which a plurality of stages having a plurality of photoelectric conversion elements in the horizontal direction are arranged in the vertical direction, and a CC for outputting electric charge from the light receiving section as an electric signal.
A solid-state image pickup means having a D shift register and a transfer gate for controlling the transfer timing of charges from the light receiving section to the CCD shift register, a density setting means for setting the density, and the density setting means. A third determination unit that determines the number of stages of the light receiving unit of the solid-state imaging unit according to the set concentration and a charge accumulated in the stages of the number of stages determined by the third determination unit are adjacent to each other. An image reading apparatus comprising: a charge transfer unit that sequentially transfers the charges to the transfer gate while sequentially adding the charges to the transfer gate. 4. A light receiving section, in which a plurality of stages having a plurality of photoelectric conversion elements in a horizontal direction are arranged in a vertical direction, and a CC for outputting electric charges from the light receiving section as an electric signal.
A solid-state image pickup means having a D shift register and a transfer gate for controlling the transfer timing of charges from the light receiving portion to the CCD shift register; a time measuring means for measuring a continuous irradiation time of an original irradiation lamp; Time determination means for determining whether or not the time measured by the means exceeds a predetermined reference time, and when the time determination means makes an affirmative determination, based on the time measured, the light amount of the original irradiation lamp And a fourth determining means for determining the number of stages of the light receiving section of the solid-state imaging means according to the light amount set by the light amount setting means, and a stage determined by the fourth determining means. Transfers the charges accumulated in several stages to the transfer gate while sequentially accumulating the charges in the adjacent next stages. Image reading apparatus characterized by comprising a charge transfer device. 5. The overflow drain according to any one of claims 1 to 4, wherein the overflow drain is disposed on the opposite side of the transfer gate with the light receiving section interposed therebetween, and the stage to which no charge is transferred to the overflow drain by the charge transfer means. And an electric charge discharging means for discharging the electric charges of the image reading apparatus.