JP2001147494A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of accurately detecting the size of an original. SOLUTION: The image forming device is provided with a means for fetching image data from an image reading sensor nearly just before an original cover is put down to a prescribed angle in a state where an exposure lamp is turned off, and then, storing the fetched image data as 1st image data, and a means for turning on the exposure lamp when the original cover is put down to the prescribed angle, also, fetching the image data from the image reading sensor and storing the fetched image data as 2nd image data, and a measuring means for measuring the widthwise length of the original based on the 1st image data and the 2nd image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document size detecting device in an image forming apparatus such as a copying machine and a facsimile machine.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a facsimile apparatus, the size of a set document is detected when the document is set on a contact glass and then closed. That is, when the document holder is tilted to a predetermined angle immediately before the document holder is completely closed, the exposure lamp is turned on, and the length of the document in the width direction is detected based on the reflected light. At the place where the document exists, the light emitted from the exposure lamp is reflected by the document,
The light emitted from the exposure lamp is not reflected at a portion where no document exists. Therefore, the presence or absence of reflected light is determined by C
The length in the width direction of the document can be detected by detecting the image by a CD or other image reading sensor.

The reason why the exposure lamp is turned on just before the document holder is completely closed to detect the length of the document in the width direction is as follows. In other words, when the document holder is open, the user may be in the process of setting the document, and it is not known whether the document is set correctly. Therefore, the document size cannot be detected accurately. If the exposure lamp is turned on when the presser is opened, it is dazzling for the user and it is difficult to set the original.

When the exposure lamp is turned on after the document holder is completely closed, light emitted from the exposure lamp is reflected by a mat formed on the document holder even in a portion where no document exists, and the document As a result, the original size is detected as reflected light from the original, and accurate document size detection cannot be performed.

The length of the document in the vertical direction is detected by a reflection type sensor.

[0006]

Conventionally, as described above, the exposure lamp is turned on immediately before the document holder is completely closed to detect the length of the document in the width direction.
When external light enters through the gap between the document holder and the contact glass, the entered external light is detected as reflected light from the document, and there is a problem that the document size cannot be accurately detected.

FIG. 6 schematically shows a conventional document size detecting method. In FIG. 6, the reflected light from the original is drawn so as to be directly incident on the condenser lens 25.
Actually, the reflected light from the document enters the condenser lens 25 via a plurality of reflection mirrors.

FIG. 6A shows a state in which the reflected light from the original S1 having a width of A4 (297 mm in width) is transmitted through the condenser lens 25 to the CCD.
FIG. Since the periphery of the document is often a white background, the size of the document is detected by using the portion where the image data obtained by the CCD 26 changes from black to white as the edge of the document. In this case, the document size is L1 on the image data D.

FIG. 6B shows a state in which reflected light from an A4 vertical (width 210 mm) original S2 is transmitted through a condenser lens 25 to a CCD.
FIG. The document size in this case is L2 on the image data D.

FIG. 6C shows a state in which the document holder is tilted to a predetermined angle and the exposure lamp is turned on, and the A4 length (width 2
10 mm) together with the reflected light from the original S2, the external light from the light source 100 such as illumination is transmitted through the condenser lens 25 to the CC.
The state where the light is incident on D26 is shown. In this case,
Since the image data corresponding to the location where the external light from the light source 100 is incident on the CCD 26 is white, the original size on the image data D is L3 instead of L1. That is, the document size is erroneously detected.

An object of the present invention is to provide an image forming apparatus capable of accurately detecting the size of a document.

[0012]

A first image forming apparatus according to the present invention takes in and takes in image data from an image reading sensor with an exposure lamp turned off immediately before a document press is tilted to a predetermined angle. Means for storing image data as first image data, when the document presser is tilted down to a predetermined angle, turns on an exposure lamp, captures image data from an image reading sensor, and stores the captured image data in a second image. It is characterized by comprising means for storing as data, and measuring means for measuring the length of the document in the width direction based on the first image data and the second image data.

In the second image forming apparatus according to the present invention, when the document holder is open and the exposure lamp is off, image data is taken in from the image reading sensor at predetermined time intervals, and the document holder is opened. Means for storing image data captured immediately before the input of the original image reading signal as first image data when the original image reading start signal is input while the original image reading start signal is input; Means for turning on the exposure lamp, fetching image data from the image reading sensor, storing the fetched image data as second image data, and the first image data and the second image data. And measuring means for measuring the length of the document in the width direction.

[0014] As the measuring means, for example, in the light receiving area of the image reading sensor, an area where the data value is inverted between black and white between the first image data and the second image data is defined as an original image area. It is determined that there is a document, and the one that measures the length of the document in the width direction is used.

The measuring means may be, for example, a region in the light receiving region of the image reading sensor in which the first image data indicates that no light is incident, and a region in which the light is incident. The area represented by the image data 2 is
The one that determines the document image area and measures the length of the document in the width direction is used.

A third image forming apparatus according to the present invention captures image data at predetermined time intervals from an image reading sensor while the exposure lamp is off immediately before the document holder is tilted to a predetermined angle, and transfers the image data. Means for storing the captured image data as the first image data and storing the previously captured image data as the third image data each time the capture is performed, turning on the exposure lamp when the document holder is tilted down to a predetermined angle; Means for fetching image data from the image reading sensor and storing the fetched image data as second image data; and, among light receiving regions of the image reading sensor, the first image data and the third image data indicating that light is not incident. Area indicating both of the image data, and that the light is incident on the second image The area over data is representative, it is determined that an original image region, characterized by comprising a measuring means for measuring the length in the width direction of the document.

The fourth image forming apparatus according to the present invention captures image data from the image reading sensor at predetermined time intervals when the document holder is open and the exposure lamp is off. Means for storing the captured image data as the first image data and storing the previously captured image data as the third image data. When a document image reading start signal is input while the document presser is open. Means for turning on an exposure lamp and fetching image data from an image reading sensor when a document image reading start signal is input, storing the fetched image data as second image data, and a light receiving area of the image reading sensor Out of the first image data and the third image data A region where both are represented and where the second image data indicates that light is incident is determined to be a document image region, and the length of the document in the width direction is measured. It is characterized by having measuring means.

When the exposure lamp is off and the image data is read from the image reading sensor at a time interval T, the commercial frequency is f [Hz], n is a natural number, and α is a real number from 1 to 9. Determined by Equation 2.

[0019]

(Equation 2)

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a copying machine will be described below with reference to the drawings.

FIG. 1 shows the configuration of a copying machine.

A contact glass 1 on which a document to be copied (copied document) is placed is provided on the upper surface of the copying machine main body. An operation display unit 4 is provided on the upper surface of the copying machine main body.
2 are provided. A document holder 41 is provided on the upper surface of the copying machine so as to be freely opened and closed. On one side of the copying machine main body, a paper feed cassette 2 is provided. An exposing mechanism, a printing mechanism, and a recording paper transport mechanism are provided in the copying machine main body.

The exposure mechanism is, as shown in FIGS. 1 and 2, a document (not shown) placed on the contact glass 1.
A first optical system traveling body 31 including an exposure lamp 21 for exposing and scanning the image of the original and a first mirror 22 for reflecting the reflected light from the original, and the light reflected by the first mirror 22 is condensed to a condenser lens 25. Second and third mirrors 2 for guiding
Second optical system traveling body 32 provided with 3, 24, condensing lens 2
, A control unit 27 to which image information and the like obtained by the CCD 26 are input, and a control unit 27
And a laser unit 28 for converting a signal from the optical signal into an optical signal (laser light). The laser beam output from the laser unit 28 irradiates the photosensitive drum 11.

When scanning the entire original, the first optical system traveling body 31 and the second optical system traveling body 32 are reciprocated in the left and right directions by a scan motor (not shown). Second
The optical system traveling body 32 has a speed of 1 of the first optical system traveling body 31.
At a speed of / 2, the moving distance of the first optical system traveling body 31 is 1 /
Move a distance of 2.

To the control unit 27, in addition to the image information obtained by the CCD 26, a signal from the operation display section 42 and the like are input. The control unit 27 has functions of controlling the entire copying machine, generating a signal for forming an image based on the output (image information) of the CCD 26 for the copy original, and outputting a control signal to the laser unit 28. ing.

The printing mechanism includes a photosensitive drum 11. The photosensitive drum 11 is driven to rotate in a direction indicated by an arrow by a main motor (not shown). Photoconductor drum 1
1 around the photosensitive drums 11 in the order of their rotation.
A charging device 12 for charging the photosensitive layer on the surface of the photosensitive layer, a developing device 13 for developing the electrostatic latent image formed on the photosensitive layer as a toner visible image, and a toner visible image formed on the photosensitive layer on recording paper. A transfer discharger 14 for transferring, a separation discharger 15 for separating recording paper from the photosensitive drum 11, a cleaning device 16 for removing toner remaining on the photosensitive drum 11 after transfer, and a photosensitive drum A static eliminator 17 for removing charges on the surface 11 is provided.

The recording paper transport mechanism transports the recording paper fed by the paper feeding roller 36 to the photosensitive drum 11 at a predetermined timing. The recording paper on which the toner image formed on the resist roller 37 and the photosensitive drum 11 is transferred and peeled from the photosensitive drum 11 is fixed to the fixing roller 3.
9 is provided. The transfer paper on which the fixing process has been performed by the fixing roller 39 is sent onto a discharge tray 43 via a discharge mechanism (not shown).

Hereinafter, a method for detecting the length of the document set on the contact glass 1 in the width direction will be described.

[1] Description of First Embodiment

After the original is set on the contact glass 1 and the exposure lamp 21 is off from when the original holder 41 is opened to when the original holder 41 is tilted to a predetermined angle, the image data of the CCD 26 is stored in a predetermined state. The data is captured at time intervals (for example, 500 ms) and stored as first image data. The first image data is updated to new image data every time new image data is captured.

When the document holder 41 is tilted to a predetermined angle, the exposure lamp 21 is turned on, and the CCD 26 at that time is turned on.
Is captured and stored as second image data. That the document holder 41 has been tilted to a predetermined angle is detected by, for example, a limit switch.

The first image data and the second image data are compared, an area where the data changes is determined to be an original image area, and the length of the original in the width direction is measured.

FIG. 3 schematically shows a document size detecting method according to the first embodiment. FIG. 3 illustrates that the reflected light from the original directly enters the condenser lens 25. However, the reflected light from the original is actually the first to third light.
The light enters the condenser lens 25 via the mirrors 22, 23 and 24.

FIG. 3A shows the first image data D1 (final value) and the second image data D2 when the original S1 of A4 width (297 mm width) is set on the contact glass 1. ing.

Immediately before the document holder 41 is tilted to a predetermined angle, if no external light is incident on the CCD 26, the first image data D1 is all black data. On the other hand, when capturing the second image data D2,
Since the light emitted from the exposure lamp 21 is reflected by the document S1 and is incident on the CCD 26, the data of the portion where the reflected light is incident is white data. Therefore, when the second image data D2 is captured, the reflected light from the original
Is changed from black data (first image data) to white data (second image data).
The document size is determined to be L1 on the image data.

FIG. 3B shows the first image data D1 and the second image data D2 when the original S2 of A4 length (width 210 mm) is set on the contact glass 1. Also in this case, the data in the area where the reflected light from the document enters the CCD 26 when the second image data D2 is captured changes from black data (first image data) to white data (second image data). The document size is determined to be L2 on the image data.

FIG. 3C shows the first image data D 1 and the second image data D 1 when external light from the light source 100 such as illumination enters the CCD 26 even when the document holder 41 is tilted to a predetermined angle. 5 shows image data D2.

In this case, since the external light from the light source 100 is incident on the CCD 26 when the final first image D1 is captured, the external light from the light source 100 is applied to the CCD 26 in the first image data D1. Only the incident portion becomes white data, and the other portions become black data.

Even when the second image D2 is captured, the external light from the light source 100 is incident on the CCD 26. Therefore, in the second image data D2, the portion where the reflected light from the original is incident on the CCD 26 The portion where external light from the light source 100 is incident on the CCD 26 becomes white data, and the other portions become black data.

Therefore, comparing the first image data D1 and the second image data D2, the portion where the external light from the light source 100 is incident on the CCD 26 remains white data, and the second image data D2 is captured. Sometimes, the data in the area where the reflected light from the original enters the CCD 26 is black data (first data).
Since the image data changes to white data (second image data), the document size is determined to be L2 on the image data. In other words, it is possible to avoid erroneously detecting a portion where the external light from the light source 100 is incident on the CCD 26 as a portion where the reflected light from the document is incident.

When a predetermined page of a book is to be copied, for example, a book is set with the document presser 41 opened, and then the start key is pressed with the document presser 41 open. (A document image reading start signal may be input). In such a case, the first
What is necessary is just to acquire image data and 2nd image data as follows.

That is, in a state where the original presser is open and the exposure lamp is off, the image data of the CCD 26 is fetched at predetermined time intervals, and an original image reading start signal is input while the original presser is open. In this case, the image data captured immediately before the document image reading start signal is input is stored as the first image data. When a document image reading start signal is input, the exposure lamp is turned on and the image data of the CCD 26 is fetched, and the fetched image data is stored as second image data.

[2] Description of Second Embodiment

In the first embodiment, the inclination angle of the original presser 41 when taking in the first image data D1 is slightly different from the inclination angle of the original presser 41 when taking in the second image data D2. ing. Therefore, when external light is incident on the CCD 26 when the first image data D1 is captured, and external light is blocked by the document holder 41 when the second image data D2 is captured and does not enter the CCD 26, In that portion, the image data changes from white data to black data between the first image data D1 and the second image data D2, and thus the portion is erroneously detected as the portion where the document exists. is there.

Therefore, in the second embodiment, it is determined that the area of the white data in the first image data D1 is a portion where external light is incident because no original exists, and the first
An area where the second image data D2 is white data among the black data areas of the image data D1 is determined to be a document image area.

FIG. 4 shows that the external light from the light source 100 is incident on the CCD 26 when the first image data
The first image data D1 and the second image data D2 when external light from the light source 100 is cut off by the document holder 41 when the image data D2 is captured and does not enter the CCD 26 are shown.

When the first image data D1 is taken in, since external light from the light source 100 is incident on the CCD 26,
In the first image data D1, only the portion where external light from the light source 100 is incident on the CCD 26 becomes white data, and the other portions become black data.

At the time of capturing the second image D2, since the external light from the light source 100 does not enter the CCD 26, the portion of the second image data D2 where the reflected light from the original enters the CCD 26. The remaining data is white data, and the other data is black data.

Then, in the black data area of the first image data D1, the area L2 in which the second image data D2 is white data is determined to be a document image area. Therefore, even when external light is incident on the CCD 26 when the first image data D1 is captured, and external light is blocked by the document holder 41 when the second image data D2 is captured, the external light does not enter the CCD 26. The document size can be accurately detected.

[3] Description of Third Embodiment

In the second embodiment, the external light is assumed to be continuous light such as natural light, light from an incandescent light bulb, or a fluorescent light controlled by an inverter. However, in a fluorescent lamp emitting light at the commercial frequency (50 Hz or 60 Hz), a moment when the fluorescent lamp is extinguished appears at a cycle (10 ms or 8.3 ms) corresponding to twice the commercial frequency.

If the timing when the first image data D1 is taken in coincides with the timing when the fluorescent lamp is turned off, the influence of the external light does not appear on the first image data D1 despite the existence of the external light. Thereafter, when the second image data is captured at the timing when the fluorescent lamp is turned on, the light from the fluorescent lamp is detected as the reflected light from the original, and the original size is erroneously detected.

Therefore, in the third embodiment, each time the first image data D1 is taken from the CCD 26 while the exposure lamp 21 is off, the latest taken first image data D1 is used as the first image data D1. The first image data D1 stored and previously captured is stored as third image data D3.

The acquisition interval of the first image data D1 is such that, even if one of the two consecutive data acquisition points coincides with the timing when the fluorescent lamp is turned off, the other data acquisition point The time is set so as not to coincide with the timing when the fluorescent lamp is turned off. That is, the capture interval of the first image data D1 is set to an interval that is not a multiple of the blinking interval of the fluorescent lamp (10 ms or 8.3 ms).

Specifically, assuming that the capture interval of the first image data D1 is T, the commercial frequency is f [Hz], n is a natural number, and α is a real number from 1 to 9, the capture interval of the first image data D1 is T is expressed by the following equation 3.

[0056]

(Equation 3)

Assuming that the commercial frequency is 50 [Hz], for example, n = 24 and α = 5.0, T = 245 ms. If the commercial frequency is 60 [Hz], for example, n = 29 and α = 4.0, T = 245 ms. Therefore, the capture interval T of the first image data D1 is
For example, it is set to 245 ms.

While the exposure lamp 21 is off, the first
The image data D1 and the third image data D3 are obtained. When the document holder 41 is tilted to a predetermined angle, the exposure lamp 21 is turned on to obtain the second image data D2.

Then, an area where at least one of the first image data D1 and the third image data D3 is white data is determined to be a part to which external light is incident because no original exists, and the first image data is determined. The area where the second image data D2 is white data among the areas where both the data D1 and the third image data D3 are black data is determined to be the document image area.

FIG. 5 shows that the commercial frequency (50 Hz or 6 Hz) is applied even when the document holder 41 is tilted to a predetermined angle.
0 Hz), the external light from the fluorescent lamp 200 emitting light at C
The first image data D1, the third image data D3, and the second image data D2 when incident on the CD 26 are shown.

In this case, at least one of the time when the third image data D3 is captured and the time when the first image data D1 is captured, the fluorescent lamp 2 is used.
External light from 00 is incident on the CCD 26. In this example, when the third image data D3 is captured, external light from the fluorescent lamp 200 is incident on the CCD 26, and the first image data D1 is output at a timing when the fluorescent lamp 200 is turned off.
Is taken in. It is also assumed that the second image data D2 is captured at the timing when the fluorescent lamp 200 is turned on.

In the third image data D3, the fluorescent light 2
Only the portion where the external light from 00 is incident on the CCD 26 becomes white data, and the other portions become black data. The first image data D1 is all black data.

In the second image data D 2, the portion where the reflected light from the original is incident on the CCD 26 and the fluorescent lamp 2
The portion where external light from 00 is incident on the CCD 26 becomes white data, and the other portions become black data.

Then, of the areas where both the third image data D3 and the first image data D1 are black data, the area where the second image data D2 is white data is determined to be the original image area. . That is, the document size is determined to be L2.

When the third image data D3 or the first image data D1 is captured, external light from the fluorescent lamp 200 is incident on the CCD 26, and when the second image data D2 is captured, external light from the fluorescent lamp 200 is input. Even in the case where the light is blocked by the document presser 41 and does not enter the CCD 26, the second image data D3 in the area where both the third image data D3 and the first image data D1 are black data are used.
By determining that the area 2 is white data as a document image area, the document size can be accurately detected.

When a predetermined page of a book is to be copied, for example, a book is set with the document holder 41 opened, and then the start key is pressed with the document holder 41 opened. (A document image reading start signal may be input). In such a case, the third
What is necessary is just to acquire image data, 1st image data, and 2nd image data as follows.

That is, in a state where the document holder is open and the exposure lamp is off, the image data of the CCD 26 is fetched at predetermined time intervals, and every time the image data is fetched, the latest fetched image data is replaced with the first image data. The image data stored last time is stored in the third
Is stored as image data. When a document image reading start signal is input in a state where the document presser is open, when the document image reading start signal is input, the exposure lamp is turned on and the image data of the CCD 26 is captured and captured. The image data is stored as second image data.

[0068]

According to the present invention, the original size can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a schematic configuration of a copying machine.

FIG. 2 is a perspective view showing an exposure mechanism.

FIG. 3 is a schematic diagram for explaining a document size detection method according to the first embodiment.

FIG. 4 is a schematic diagram for explaining a document size detection method according to a second embodiment.

FIG. 5 is a schematic diagram for explaining a document size detection method according to a third embodiment.

FIG. 6 is a schematic diagram for explaining a conventional document size detection method.

[Explanation of symbols]

 21 Exposure Lamp 22 First Mirror 31 First Optical System Traveling Body 23 Second Mirror 24 Third Mirror 25 Condensing Lens 32 Second Optical System Traveling Body 26 CCD 27 Control Unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroyuki Harada, Inventor 1-2-28 Tamazo, Chuo-ku, Osaka, Osaka Inside Mita Kogyo Co., Ltd. (72) Aiko Aono 1-2-2, Tamazo, Chuo-ku, Osaka, Osaka No. 28 F term in Mita Industries Co., Ltd. (reference) 2F065 AA22 CC02 FF04 JJ03 JJ26 QQ24 QQ31 RR03 2H107 AA01 AB06 AB22 BA13 DA03

Claims (7)

[Claims] 1. A means for fetching image data from an image reading sensor and storing the fetched image data as first image data in a state immediately before the document holder is tilted down to a predetermined angle while the exposure lamp is off. Means for turning on the exposure lamp and fetching image data from the image reading sensor when the presser is tilted down to a predetermined angle, storing the fetched image data as second image data, and first and second image data.
Measuring means for measuring the length of the document in the width direction based on the image data. 2. An image reading sensor receives image data at predetermined time intervals from an image reading sensor in a state where a document holding member is opened and an exposure lamp is turned off. Means for storing, as first image data, image data taken immediately before a document image reading start signal is inputted when the document image reading start signal is inputted; turning on an exposure lamp when a document image reading start signal is inputted; Means for fetching image data from the image reading sensor and storing the fetched image data as second image data; and a length in the width direction of the document based on the first image data and the second image data. An image forming apparatus comprising: measuring means for measuring 3. A document image area of a light receiving area of an image reading sensor, wherein a data value is inverted between black and white between a first image data and a second image data. The image forming apparatus according to claim 1, wherein the length of the document in the width direction is measured. 4. The measuring means is a region in the light receiving region of the image reading sensor, in which the first image data indicates that no light is incident, and indicates that the second light is in the second light receiving region. 3. The document size of the image forming apparatus according to claim 1, wherein the area represented by the image data is determined to be a document image area, and the length of the document in the width direction is measured. Detection device. 5. Immediately before the document holder is tilted to a predetermined angle, image data is captured from the image reading sensor at predetermined time intervals while the exposure lamp is off, and the captured image data is read every time the image data is captured. Means for storing one image data and storing the previously captured image data as third image data; when the document presser is tilted down to a predetermined angle, the exposure lamp is turned on and the image data is captured from the image reading sensor; Means for storing the captured image data as second image data, and both the first image data and the third image data indicate that no light is incident on the light receiving area of the image reading sensor. An area where the second image data indicates that light is incident is defined as a document image It is determined that a frequency, with which an image forming apparatus comprising a measuring means, for measuring the length in the width direction of the document. 6. When image data is taken in at predetermined time intervals from an image reading sensor in a state where a document presser is open and an exposure lamp is off, the image data taken every time image data is taken is taken as a first image. Means for storing data as data and storing previously captured image data as third image data; when a document image reading start signal is input while the document presser is open, a document image reading start signal is input; Means for turning on the exposure lamp, capturing image data from the image reading sensor, and storing the captured image data as second image data.
In the light receiving area of the image reading sensor, the first image data and the third image data both indicate that light is not incident, and the second area is that light is incident. Measuring means for judging that the area represented by the image data is an original image area and measuring the length of the original in the width direction. 7. When the exposure lamp is turned off and the commercial data frequency is f [Hz], n is a natural number, and α is a real number from 1 to 9, the time interval T for taking image data from the image reading sensor is as follows. The image forming apparatus according to claim 5, wherein the image forming apparatus is determined by Expression 1. (Equation 1)