JP5171659B2 - Image forming apparatus - Google Patents

Description

  The present invention includes a first image sensor that reads surface information of a document conveyed by a document conveying device via a mirror scanning optical system, and executes a gain adjustment of the first image sensor when the power is turned on. The present invention relates to an image forming apparatus including an input unit and a contact-type second image sensor that is incorporated in the document conveying device and reads back side information of a document conveyed by the document conveying device.

In an image forming apparatus such as a copying machine that reads and prints both sides of an original, both sides of the original are read simultaneously by two reading means.
As an example of this, an image reading apparatus for improving the processing speed at the time of single-sided reading of a document has been proposed (see Patent Document 1).
The image reading apparatus is provided at a branch point between a first document transport path and a second document transport path, and a switching unit capable of selectively transporting a sheet document to each document transport path, and a first document A first image reading means (CIS1) that reads an image on one side of a sheet-like document conveyed on the conveyance path, and a second document that reads an image on the opposite side of the sheet-like document conveyed on the first document conveyance path Reading means (CIS2).

This image reading apparatus alternately conveys originals to two original conveyance paths in the single-sided flow reading mode, and reads images of two originals simultaneously by two image reading means (CIS1, 2).
In addition to this, the document processing speed at the time of single-sided scanning reading is increased as compared with the conventional image reading apparatus capable of simultaneous double-sided reading by increasing the document conveying speed other than the time of image reading from a predetermined document reading speed. Can be improved.

There has also been proposed an image reading apparatus for preventing a reduction in document reading speed and improving productivity (see Patent Document 2).
This image reading apparatus includes a charge coupled device (CCD) type CCD image sensor (CCD) using a reduction optical system that reads image information on one side of a document and outputs an image signal, and other documents. A contact type image sensor (CIS: Contact Image Sensor) that reads image information of a direction and outputs an image signal, a selection unit that selects one side or both sides of a document, and an operation of each unit It has control means for controlling.

The image reading apparatus configured as described above can prevent a reduction in the double-sided reading speed of the original when the reading speed is set to be optimal for the CIS operation when reading the front side and the back side of the original at the same time.
When reading only the front side or the back side of a document, setting the optimum reading speed for the operation of each CCD or CIS sensor can prevent a decrease in the document reading speed and improve productivity. It is.

JP 2006-140902 A JP 2007-74367 A

By the way, an image reading apparatus having two CCDs as in Patent Document 1 and an image reading apparatus having CCDs and CISs as in Patent Document 2 are usually initialized when the power is turned on or when returning from the energy saving mode. Executed.
In this initialization, in the case of a CCD, since there is a variation in sensitivity for each pixel, shading correction for correcting the read image data of the document to an appropriate value is performed. Further, in CIS, since there is variation between sensor chips, shading correction is performed on image data read from a document to absorb them.

Furthermore, during this shading correction, automatic gain control (AGC: Automatic Gain Control) is performed to adjust the related parameters so that the maximum dynamic range (gradation reproducibility) can always be secured within the gradation range to be reproduced. The
The shading correction and gain adjustment generally take several seconds to several tens of seconds. Since neither of the image reading apparatuses of Patent Documents 1 and 2 can shorten the initialization operation, the document reading speed is increased. There was a certain limit.

  That is, this type of image reading apparatus performs the above-described gain adjustment when the document transport mechanism is set in a predetermined state after the power is turned on. This gain adjustment is slightly different depending on the model of the image reading apparatus, but the DP (Document Processor) cover that covers the document transport mechanism, the optical system, etc. is closed, and stray light from outside light does not enter the CIS. Need to do below.

Therefore, if the DP cover 12 (see FIG. 1) is closed when the power is turned on, the gain adjustment is possible. Therefore, the gain adjustment is performed immediately when the start key is operated, and the document reading is on standby. I was letting.
Since this gain adjustment is executed regardless of the single-sided reading mode or the double-sided reading mode of the document, the user is forced to wait for several seconds to several tens of seconds as described above, and slows down the document reading speed. There was a problem of fading.

  In view of the above-described problems, the object of the present invention is to perform the gain adjustment immediately when the single-sided scanning mode is selected and the start key is operated, even if the gain adjustment is possible, An object of the present invention is to provide an image forming apparatus capable of speeding up a document reading operation by giving priority to reading.

In order to achieve the above-mentioned object, the first characteristic configuration of the image forming apparatus according to the present invention is that the surface information of the document conveyed by the document conveying device is mirrored as described in claim 1 of the claims. A first image sensor that reads through a scanning optical system; and a first image input unit that performs gain adjustment of the first image sensor when the power is turned on; A contact-type second image sensor that reads back side information of a document to be conveyed is provided, and the gain adjustment of the second image sensor is executed when the document conveying device is set in a predetermined state after power-on. A two-image input unit, a duplex reading mode for simultaneously reading information of a document conveyed by the document conveying device by the first image input unit and the second image input unit, and the first image An image forming apparatus comprising: a reading mode setting unit that selects one of single-sided reading modes that are read only by a force unit; and an operation unit that includes a start key that activates a document reading operation. When selected and the start key is operated, the second image input unit stops executing the gain adjustment even when the document conveying device is set in a predetermined state and gain adjustment is possible. Even when the document conveying device is set in a predetermined state and gain adjustment is started, execution of gain adjustment is interrupted immediately after the start key is operated. is there.

When the single-sided reading mode is selected and the start key is operated, the second image input unit is configured to adjust the gain even if the document feeder is set in a predetermined state and gain adjustment is possible. Even if the document conveying device is set to a predetermined state and gain adjustment is started, the gain adjustment is interrupted immediately after the start key is operated. The surface information of the original to be read can be read by the first image sensor.
Therefore, when the single-sided reading mode is selected and the start key is operated, when the gain adjustment is possible as in the prior art, the gain adjustment is executed immediately to wait for the reading of the document. The problem is solved and the document reading operation is speeded up.

  According to the second characteristic configuration of the image forming apparatus of the present invention, as described in claim 2 of the document of the claims, in addition to the first characteristic configuration described above, the second image input unit includes the one side surface. In the reading mode, the gain adjustment is performed after the reading operation of the document is completed.

  Since the second image input unit performs gain adjustment after the reading operation of the document is completed in the single-sided reading mode, the necessary gain adjustment can be performed after the reading of one side of the document is completed. The document reading operation is accelerated by the time required for adjustment.

  As described above, according to the present invention, when the single-sided reading mode is selected and the start key is operated, even if gain adjustment is possible, the gain adjustment is not performed immediately, and the document surface information is read. It is now possible to provide an image forming apparatus that can speed up the document reading operation with priority given to.

Vertical section showing image forming device Perspective view of the second image input unit Block diagram showing electrical configuration of image forming apparatus Flowchart for explaining initialization operation of image forming apparatus Flowchart for explaining printing operation of image forming apparatus

The image forming apparatus according to the present invention will be described below.
The image forming apparatus is applied to an electrophotographic copying machine. As shown in FIG. 1, an image reading device 2 is provided above the copying machine. The image reading apparatus 2 includes a document table 21 on which a document is placed, a document transport mechanism 3 that transports the document to the image reading positions 40 and 50 and discharges the scanned document, and reads the surface of the document. A first image reading unit 4 as one image input unit, a second image reading unit 5 as a second image input unit of the present invention for reading the back side of the document, and an operation unit (not shown) are configured.

  The document transport mechanism 3 includes a pickup roller 31 that picks up one document from a plurality of documents, a separation roller 32 that separates documents when the document is fed by the pickup roller 31, and a leading end of the separated document. Registration roller 33 for adjusting, paper feed roller 34 for transporting the original to downstream image reading positions 40 and 50, paper discharge roller 35 for discharging the read original, and paper discharge for storing the discharged original The tray 36 is configured.

  The document transport mechanism 3 is covered with a DP cover 12 together with the platen roller 13, the optical system, each circuit portion, and the like. The DP cover 12 is pivotally supported at the base end by a hinge provided in the vicinity of the paper feed roller 34 and can be opened and closed.

When the DP cover 12 is closed as shown in FIG. 1, the DP cover 12 covers the pickup roller 31, the separation roller 32, the registration roller 33, the paper feed roller 34, the platen roller 13, and the like. This prevents external light from entering the first image reading unit 4, the second image reading unit 5, the contact glass 37, the reference white plate 38, the glass 39, and the like.
An opening / closing detection sensor for detecting opening / closing of the DP cover 12 is provided in the vicinity of the DP cover 12 so that a detection signal corresponding to the opening / closing is sent to the system control unit 10 described later. .

  The first image reading unit 4 includes a first light source 41 that illuminates the document, a first mirror 42 that captures reflected light from the document, a second mirror 43, a third mirror 44, and the third mirror 44. A first image on the contact glass 37 is configured to include a lens 45 that focuses a light bundle on a linear CCD (hereinafter also referred to as a CCD) 46 and a CCD 46 as a first image sensor of the present invention that reads image information. The image information on the surface of the document is read at the reading position 40.

As shown in FIG. 2, the second image reading unit 5 includes a CIS unit (CIS) 51 as a second image sensor of the present invention which is a contact image sensor, and a conveyance roller 52 disposed to face the CIS 51. ing.
The CIS 51 includes a CCD substrate 53 on which a control unit for controlling the CIS 51 is mounted, a light receiving element 54 in which a plurality of sensor chips are arranged on the CCD substrate 53 along the main scanning direction, and a lower portion of the light receiving element 54. Are supported by a side casing 58. The rod lens array 55 is disposed opposite to the rod lens array 55, the second light source 57 is a xenon lamp disposed on both sides of the rod lens array 55, and the contact glass 56 is supported.

  The transport roller 52 is used as a white reference chart for reading white reference data for shading correction, with white paint applied on the surface.

  The second image reading unit 5 collects, with the rod lens array 55, the reflected light from the document D conveyed below the contact glass 56 among the light emitted from the second light source 57 at the second image reading position 50. The image information on the back side of the document D is read by receiving the light and receiving light by the light receiving element 54.

  As shown in FIG. 3, the copier 1 forms a toner image on the basis of image data input from the computer terminal and a network control unit (not shown) connected to the computer terminal via the network. An image processing unit including a printer engine 8 that transfers and fixes an image to a sheet and outputs the sheet, an engine control unit 80 that controls the printer engine 8, and an ASIC (Application Specific Integrated Circuit) that processes image data 9, a reading control unit 20 that controls the document reading unit 2, an operation control unit 70 that controls the operation unit 7, a memory (not shown) that stores image data and the like, and controls the memory and the copying machine 1. The system control unit 10 that performs overall control has a bus (for example, a command bus (a bus indicated by a thin line in the figure) 100) and an image bus (a bus indicated by a bold line in the figure). ) 101) via a are connected.

  The network control unit, the engine control unit 80, the operation control unit 70, and the system control unit 10 are each composed of a CPU, a ROM that stores an operation program of the CPU, a RAM that is a work area of the CPU, and a board that includes peripheral circuits. ing.

The reading control unit 20 receives the setting data transmitted from the operation control unit 70 via the system control unit 10 when various modes are input and set on the operation unit 7, and operates the document reading unit 2. Is controlled to read the original from the original conveying mechanism 3 and send the image data to the image processing section 9.
The setting mode includes a double-sided reading mode in which an original is simultaneously read by the first image reading unit 4 and the second image reading unit 5 and a single-sided reading mode in which only the first image reading unit 4 is read.
In this single-sided reading mode, in addition to the normal single-sided reading program, when the copy key is operated, the DP cover 12 close detection signal is received from the open / close detection sensor, and even if gain adjustment is possible, the gain is adjusted immediately. Is included, and a program that prioritizes reading of the surface information of the document is included.

  The operation control unit 70 sends a command signal to the system control unit 10 when various types of information are input through the hard key 7b of the operation unit 7 or the touch panel of the display unit 7a. When a display command is sent from the system control unit 10, a screen indicating that the copying machine 1 is performing a printing operation is displayed on the display unit 7 a of the operation unit 7.

  The display unit 7a is provided with a touch panel, which displays a menu and allows various inputs. This menu includes document reading settings in addition to copy initial settings, printer initial settings, machine initial settings, and the like. The original reading setting includes a single-sided reading setting for reading one side of the original and a double-sided reading setting for reading both sides simultaneously.

  As shown in FIG. 1, in the document reading device 2, when a document is placed on a contact glass 37 for placing a document, the first light source 41 and the mirrors 42, 43, 44 are arranged from the leading end side to the trailing end side of the document. The first image reading unit 4 scans (sub-scans) the image information of the document and operates in a mirror scanning mode.

When the document is transported by the document transport mechanism 3, the first light source 41 and the mirrors 42, 43, 44 are fixed at the positions indicated by the solid lines in the drawing and transported (sub-scanned) by the document transport mechanism 3. It is configured to be switchable so as to operate in a sheet through mode in which image information of a document is read by the first image reading unit 4 or the second image reading unit 5.
Accordingly, when reading a double-sided document in the sheet through mode, the image information on both sides of the document is read almost simultaneously by the first image reading unit 4 and the second image reading unit 5.

Each of the image reading units 4 and 5 is provided with a shading correction unit (not shown) for correcting the image data of the original read by the CCD 46 and the light receiving element 54 having sensitivity variations for each pixel to an appropriate value. ing.
For example, the shading correction unit samples white reference data and black reference data in advance as reference data for correction, and corrects image data obtained by reading an actual document based on the reference data.

At the time of correction, the first image reading unit 4 moves in the right direction in FIG. 1 (a position where the first mirror 42 faces the reference white plate 38), and the reference white plate 38 is irradiated by the first light source 41. When the reflected light is read by the CCD 46, first light quantity correction reference data for correction is output. The first image data read from the surface of the document with the first light quantity correction reference data is subjected to shading correction.
As described above, since the CCD 46 is constituted by a single sensor chip and the light source 41 is also located at a distance, it is sufficient to sample the shading correction data at the initial stage of the document reading operation.

  On the other hand, the light receiving element 54 is composed of a plurality of sensor chips, and the lamp 57 serving as a heat source is arranged in the vicinity, so that the output characteristics fluctuate greatly, and the variations between the sensor chips fluctuate. Therefore, it is necessary to sample shading correction data periodically to absorb them.

Based on the above, the first image reading unit 4 samples reference data for shading correction at the initial stage of reading the image information of the document.
That is, the black reference data is sampled with the first light source 41 turned off, and then the reflected light from the reference white plate 38 is sampled as white reference data with the first light source 41 turned on. Thereafter, shading correction is performed on the image data read from the document based on the reference data read at this time.

On the other hand, in the second image reading unit 5, for example, either white reference data or black reference data is alternately sampled between the document continuously conveyed by the document conveyance mechanism 3 and the document.
That is, black reference data is sampled with the second light source 57 initially turned off, and then the reflected light from the transport roller 52 is sampled as white reference data with the second light source 57 turned on.
Thereafter, black reference data and white reference data are alternately sampled between the trailing edge of the document conveyed by the document conveying mechanism 3 and the leading edge of the next document. When sampling the black reference data, the second light source 57 is turned off and turned on again after the sampling is completed. Thereafter, shading correction is performed on the image data read from the document based on the reference data read immediately before.

The correction value in this shading correction is calculated by the system control unit 10 that receives the output data.
For example, when the reflected light from the reference transport roller 52 is read as the white reference data D _WH for shading correction, as shown in Equation 1, and a black reference level D _BK read before lighting the light source 57 It calculates the image data D _iN of the document read on the basis of the white reference data D _WH above.

Ｄ_ＯＵＴ＝Ｃ×（Ｄ_ＩＮ−Ｄ_ＢＫ）／（Ｄ_ＷＨ−Ｄ_ＢＫ）

D _OUT = C × (D _IN −D _BK ) / (D _WH −D _BK )

Here, C is a bit conversion constant when converting from the output data D _IN of the image sensor to correct the output data D _OUT.
As a result, the corrected output data D _OUT is obtained as a shading correction value, and shading correction can be performed based on this correction value.

In addition, the system control unit 10 performs automatic gain adjustment (AGC) for the CCD 46 and the light receiving element 54.
Although not shown in the figure, an image signal that is a read output of the CCD 46 is input to an amplifier as a gain adjusting unit and amplified. The image signal amplified by the amplifier is input to the A / D converter, and the image signal, which is an analog signal, is converted into a digital signal and supplied to the system control unit 10.

Similarly, an image signal that is a read output of the light receiving element 54 is input to an amplifier and amplified. The image signal amplified by the amplifier is input to the A / D converter, and the image signal, which is an analog signal, is converted into a digital signal and supplied to the system control unit 10.
On the other hand, the system control unit 10 supplies a gain adjustment signal to each amplifier. As a result, each amplifier is calibrated by the AGC being applied by the system control unit 10 and the gain value being set.

By the way, this AGC is executed as an initialization process by the system control unit 10 when the power is turned on.
In this AGC, related parameters are appropriately adjusted for each set so that the maximum dynamic range (gradation reproducibility) can always be secured within the range of gradations to be reproduced. This adjustment is a composite of three types of black level, white level, and color level, and the same processing is performed for both the CCD 46 and the light receiving element 54.

  Here, the CIS 51 side which is the light receiving element 54 will be described.

First, in the black level adjustment, an output level in a state where the lamp 57 is turned off is adjusted by using an offset function of a gain setting of an amplifier (AFE) that amplifies a signal output from the light receiving element 54.
The black level adjustment is performed for the three colors RGB. The actual adjustment is performed by adjusting the AFE offset setting of the CIS 51 so that the output with the lamp 57 turned off matches the target value.

Next, in the white level adjustment, the output level at the time of reading the white reference of the conveyance roller 52 is adjusted by the opening time of the electronic shutter with the lamp 57 turned on.
Note that the white level adjustment cannot be made for each color, so the adjustment is made for one color having the highest output level. The actual adjustment is performed by adjusting the interval width of the CIS 51 Tint (brightness) signal so that the output when reading the white reference with the lamp 57 turned on matches the target value.

Subsequently, in the color level adjustment, the output level at the time of reading the white reference plate (conveying roller 52) in a state where the lamp 57 is turned on is adjusted by gain amplification of AFE. This color level adjustment is performed for two colors other than those adjusted by the white level adjustment.
The actual adjustment is performed by adjusting the AFE gain setting of the CIS 51 so that the output at the time of reading the white reference with the lamp 57 turned on matches the target value.

  In the copying machine 1 configured as described above, since the CCD 46 and the light receiving element 54 in the document reading apparatus 2 vary in sensitivity from pixel to pixel, initialization is performed to apply AGC when the power is turned on or when returning from the energy saving mode. It is supposed to be.

Next, the initialization operation of the copying machine will be described in detail with reference to the flowchart shown in FIG.
When the user turns on the power of the copying machine 1 or returns from the energy saving mode (SA1), the system control unit 10 first executes AGC on the CCD 46 side (SA2). Thereby, the gain of the CCD 46 is adjusted by the processing as described above.

Next, the system control unit 10 checks the detection signal of the open / close detection sensor and determines whether or not the DP cover 12 is closed (SA3).
Here, when the DP cover 12 is closed, AGC of the light receiving element 54 on the CIS 51 side is executed (SA4), and it is determined whether or not the fixing temperature of the fixing device is an appropriate value (SA5).

On the other hand, when the DP cover 12 is not closed from the detection signal of the open / close detection sensor, the AGC of the light receiving element 54 is not executed and the process proceeds to step SA5. Then, it is determined whether or not the fixing temperature of the fixing device is an appropriate value, and when the fixing temperature becomes an appropriate value, the copying is enabled (SA6).
At this time, since the gain of the CCD 46 is adjusted, it is possible to read the front side of the document.

  Thereafter, the system control unit 10 determines whether or not the AGC of the light receiving element 54 is completed (SA7). If the AGC of the light receiving element 54 has not ended, the process proceeds to step SA3, and the system control unit 10 determines again the opening / closing of the DP cover 12 based on the detection signal of the opening / closing detection sensor (SA3).

When the DP cover 12 is closed, AGC of the light receiving element 54 is executed (SA4), and then the fixing temperature of the fixing device is determined (SA5). At this time, since the AGC of the light receiving element 54 is executed, the copying is enabled when the fixing temperature reaches an appropriate value.
Thereafter, in the next step SA7, it is determined that the AGC of the light receiving element 54 has been completed, and the series of initialization operations are ended.

When the initialization is performed as described above, the copy is possible, but the usage mode of the copying machine 1 varies depending on the user.
For example, the DP cover 12 may be opened immediately after the power is turned on, closed after being opened, or left open for a while.
When the DP cover 12 is opened, stray light enters the copying machine 1 as described above. Therefore, the AGC according to the characteristics of the first image reading unit 4 and the second image reading unit 5 and the printing operation in accordance with the copy settings. Must be executed.

Next, the operation of the copying machine in the print mode will be described in detail with reference to the flowchart shown in FIG.
While waiting for the printing operation (SA11), the system control unit 10 checks the detection signal of the open / close detection sensor to determine whether the DP cover 12 is closed (SA12).

  Here, when it is determined that the DP cover 12 is closed, the above-described AGC of the light receiving element 54 is started (SA13). Then, the output of the operation control unit 70 is checked to determine whether or not there is a copy key operation (SA14).

On the other hand, when the DP cover 12 is opened, stray light enters the CIS 51. Therefore, the AGC of the light receiving element 54 is not started, and the process proceeds to step SA14 to determine whether or not the copy key is operated.
Here, when there is no operation of the copy key, the process proceeds to step SA12, and it is determined again whether or not the DP cover 12 is closed.

Thereafter, when there is an operation of the copy key, the system control unit 10 determines whether or not copying by the operation is selection of double-sided copying (SA15).
If double-sided copying is selected in step SA15, the system control unit 10 determines whether or not the AGC adjustment is completed (SA16).
If the adjustment of the AGC of the light receiving element 54 has not been started yet, the system control unit 10 starts the AGC of the light receiving element 54 (SA27).

Then, double-sided copying is executed when the AGC adjustment of the CCD 46 and the light receiving element 54 is completed (SA17). If double-sided copying is selected, even if the copy key is operated while the DP cover 12 is not closed, copying is not started until the DP cover 12 is closed.
Thereafter, it is determined whether or not double-sided copying is finished (SA18), and when double-sided copying is finished, a series of double-sided copying operations are finished.
Thus, after both sides of the original are read with the DP cover 12 closed, the image is copied on both sides of the paper.

On the other hand, when double-sided copy is not selected in step SA15, the system control unit 10 determines whether or not the AGC adjustment on the CCD 46 side has been completed (SA19).
In SA19, when the adjustment of the AGC on the CCD 46 side is completed, the system control unit 10 determines whether or not the DP cover 12 is open (SA28).

In step SA28, when the DP cover 12 is opened, the process proceeds to step SA20.
That is, at this time, since single-sided copying is selected, even if the DP cover 12 is opened, single-sided copying is executed when the AGC adjustment on the CCD 46 side is completed (SA20).
Thereafter, it is determined whether or not single-sided copying is completed (SA21), and when the single-sided copying is completed, a series of single-sided copying operations are ended.

Thus, even when the DP cover 12 is opened, the image is copied on one side of the paper after the surface of the original is read.
Therefore, when the single-sided copy is selected, the surface of the original is read immediately, so that the original reading operation is speeded up and the entire copy time is shortened.

  On the other hand, when the DP cover 12 is closed in step SA28, the AGC adjustment of the light receiving element 54 can be executed, or the AGC adjustment of the light receiving element 54 is being executed. The system control unit 10 does not start the adjustment of the AGC of the light receiving element 54 (that is, stops the execution of the gain adjustment), or interrupts the execution of the AGC adjustment of the light receiving element 54 that is being executed (SA22). . Then, one-sided copying is immediately executed (SA23).

Thereafter, it is determined whether or not single-sided copying has been completed (SA24). If the AGC adjustment of the light receiving element 54 has been interrupted when single-sided copying has been completed, the adjustment is resumed (SA25). When this AGC adjustment is completed (SA26), a series of single-sided copying operations are terminated.
Therefore, as in the prior art, when the AGC is possible, the so-called standby time in which the AGC is immediately executed to wait for the document reading is eliminated, and the document reading operation is speeded up. As a result, the copy time is greatly shortened.

  As described above, the image forming apparatus according to the present invention includes the first image sensor 46 that reads the surface information of the document conveyed by the document conveying device 3 through the mirror scanning optical system, and the first image sensor 46 is turned on when the power is turned on. A first image input unit 4 that performs gain adjustment of the image sensor 46; and a contact-type second image sensor 51 that is incorporated in the document conveying device 3 and reads back side information of the document conveyed by the document conveying device 3. After the power is turned on, the second image input unit 5 that performs gain adjustment of the second image sensor 51 when the document conveying device is set in a predetermined state, and information on the document conveyed by the document conveying device 3 , A reading mode setting for selecting either a double-sided reading mode for simultaneous reading by the first image input unit 4 and the second image input unit 5 or a single-sided reading mode for reading by only the first image input unit 4 And an operation unit 7 including a start key for starting a document reading operation. When the single-sided reading mode is selected and the start key is operated, the second image input unit 5 causes the document conveying device 3 to be in a predetermined state. Even if the gain adjustment is possible, the execution of the gain adjustment is interrupted or stopped.

  The second image input unit 5 is configured to perform gain adjustment after the reading operation of the document in the single-sided reading mode.

  In the above-described embodiment, the copying machine 1 to which the present invention is applied has been described. However, the present invention is not only applicable to the copying machine 1 alone. That is, the present invention can be applied to a document reading unit included in a so-called multifunction machine.

  The above-described embodiments are merely examples of the present invention, and the scope of the present invention is not limited by the description, and the specific configuration of each part is appropriately changed within the scope of the effects of the present invention. It goes without saying that it can be done.

3: Document feeder 4: First image input unit 5: Second image input unit 46: First image sensor 51: Second image sensor

Claims (2)

A first image input unit that includes a first image sensor that reads surface information of a document conveyed by a document conveying device via a mirror scanning optical system, and that performs gain adjustment of the first image sensor when the power is turned on;
A contact-type second image sensor that is incorporated in the document conveying device and reads back side information of a document conveyed by the document conveying device, and the document conveying device is set in a predetermined state after the power is turned on; A second image input unit for performing gain adjustment of the second image sensor;
Select one of the double-sided reading mode for simultaneously reading the information of the original conveyed by the original conveying device by the first image input unit and the second image input unit, and the single-sided reading mode for reading only by the first image input unit. An image forming apparatus comprising: a reading mode setting unit for performing an operation unit including a start key for starting a document reading operation;
When the one-side reading mode is selected and the start key is operated, the second image input unit is configured to adjust the gain even when the document conveying device is set in a predetermined state and gain adjustment is possible. The image formation is configured such that the execution of the gain adjustment is interrupted immediately after the start key is operated even when the document conveying device is set in a predetermined state and the gain adjustment is started. apparatus.   The image forming apparatus according to claim 1, wherein the second image input unit is configured to perform gain adjustment after the document reading operation is completed in the single-sided reading mode.

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