JP2001324770A - Image forming device, and its control method and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an original size detection ability to an original which is only readable at a level difficult to detect at the time of opening a pressing plate, and which is decreased in a reading value because the original has low brightness and transmits the light emitted thereto. SOLUTION: This image forming device is characterized in being configured so that a controller 110 executes an image original size detection sequence by controlling driving of a light source 707, a CCD 701, and a reflection type original size detection sensor 105 based on the opening/closing state detection result of the pressing plate by a pressing plate state detection sensor 710 and also controls to amplify an image signal detected by the CCD 701, and judges the size of the original placed on the original platen based on the detection result of the amplified detection image signal and the reflection type original size detection sensor 105 at the time of executing the original size detection sequence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original platen glass on which an image original is set, and an openable and closable original platen for pressing the image original set on the original platen glass so as not to float on the original platen glass. Irradiating means for irradiating light to an image original placed on the platen glass; and inputting reflected light from the image original by irradiation of the irradiating means to read the image original and to output an image signal. The present invention relates to an image forming apparatus having a reading unit for outputting, a control method of the image forming apparatus, and a storage medium.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, the following two methods are generally used as a method for detecting the size of a document on a platen glass.

A first method is to detect the size of a document on a platen glass while a pressure plate detection sensor for detecting a closed state (open state) of a document pressure plate (hereinafter simply referred to as a pressure plate) is ON. The size of the original is detected by a reflection type size detection sensor and an image reading unit (constituted by a light source for irradiating the original, a CCD image sensor for reading the reflected light from the light source, etc.)
Then, the state of the document in the process of closing the document pressing plate is monitored at regular intervals for a predetermined time, and the document size detection result after the predetermined time is used as document size detection data in the pressure plate closed state.
The document size is detected (determined) on the platen glass based on these document size detection results.

In the first method, as described above, when detecting a document in the open state and the closed state of the pressure plate, the document size is continuously detected for a predetermined time from the time when the pressure plate is closed. However, since the moment when the pressure plate is closed is not known, the detection of the original size is terminated by the timer control.
If the pressure plate is not closed in a predetermined time, the size of an original having a high density becomes undefined. In the case of a document with a high density, the reflected light from the sensor is weak and an appropriate size may not be detected. In the state where the platen is not completely closed, the detection light (reflected light) returns to the sensor in both the document area and the area outside the document. Because there is no original, there is no original, but an accurate original size is determined by using the white level outside the original area when the pressure plate is closed.

A second method is to provide a pressure plate detection sensor for detecting a state (open state) of the document pressure plate being closed and a magnet SW for detecting a state in which the pressure plate is completely closed on the back of the operation panel. , The closed state of the platen is detected by performing the SW control with the repulsive force of the magnet attached to the platen side, and the document size on the platen glass is determined based on the document size detection results in the pressed platen open state and the platen open state. This is a method of detecting (determining).

In the second method, the state in which the pressure plate is completely closed can be detected. Therefore, when the pressure plate is almost closed (the pressure plate is opened), the portion where the sensor level does not change when the pressure plate is closed is determined as the document size. You.

[0007]

Regarding the above two methods, in the first method, after the pressure plate detection sensor is turned on, the detection of the document size is stopped after a predetermined time has passed by the timer circuit, so that the pressure plate is completely In the case of a time-out situation before the document is closed, the outside area of the document becomes a no-signal state in the document size detection by the reflection type size detection sensor or the image reading unit because the pressure plate is not completely closed. There is a problem that it is difficult to discriminate a low-luminance density document area from a non-document area, and the accuracy of low-luminance density document discrimination ability is limited.

Similarly, in the second method, although the state detection of the pressure plate is reliable, it cannot be realized unless each of the main body side and the pressure plate side has a structure capable of detecting the closed state, so that it becomes expensive. There was a problem.

Therefore, in order to avoid an increase in cost, for example, in the case of a system using an inexpensive white pressure plate or the like, it becomes difficult to discriminate the white pressure plate region from the original region when detecting the original size. There was a problem that led to a decline in ability.

[0010] Further, in a thick original such as a book or an original whose end portion is raised, the relative distance from the sensor is increased, so that the level of the reflected light is reduced and erroneous detection is likely to occur. Further, a light-transmission type original such as the second original drawing paper has a problem that reflected light tends to be extremely small, and similar erroneous detection is likely to occur.

Also, in the conventional image forming apparatus, the original size detection is performed while the setting of the image reading unit is the same as the setting at the time of normal image reading (circuit setting, circuit gain, light amount, etc. at the time of image reading). There is no method for improving the detection accuracy for a black document, that is, a document having a low luminance density.

The present invention has been made to improve the accuracy of detecting the size of a document as described above. It is an object of the first invention to the eleventh invention according to the present invention to provide a method for mounting the document pressure on the plate mounting position. Based on the detection result of the open / close state of the document pressure plate provided by the pressure plate state detection sensor provided in the vicinity, the drive of the image reading unit (light source, CCD image sensor, etc.) and the document size detection sensor are controlled to execute the image document size detection sequence. Control to amplify the detected image signal by the image reading unit, and based on the amplified detection image signal and the detection result of the reflection type document size detection sensor, when performing the image document size detection sequence, the platen glass By judging the size of the original placed on top, it can be read only to a level that is difficult to detect when the pressure plate is opened, and the luminance density is low. The ability to detect the size of a document, which reduces the reading value due to transmission of the document or the document irradiation light, can be improved, and the same conditions can be detected regardless of the type of the document pressure plate and the document feeding device. The result can be obtained. As a result, the original size can be correctly adjusted even when a thick copy such as a book with the original platen open and the original having a raised end portion are used as the Book copy or the second original drawing paper. An object of the present invention is to provide an image forming apparatus capable of detecting and performing an appropriate copying operation, a control method of the image forming apparatus, and a storage medium.

[0013]

According to a first aspect of the present invention, there is provided a platen glass (a platen glass 111 shown in FIG. 2) on which an image document is set and an image document set on the platen glass. An openable and closable document pressure plate (document pressure plate shown in FIG. 2) for pressing the document platen glass so as not to float, and an irradiating means for irradiating light to the image document placed on the platen glass ( 8. An image forming apparatus comprising: a light source 707 shown in FIG. 8; and a reading unit (CCD 701 shown in FIG. 8) for inputting reflected light from an image original by irradiation of the irradiation unit, reading the image original, and outputting an image signal. In the apparatus, a platen state detecting means (a platen state detecting sensor 71 shown in FIG. 8) for detecting an open state and a closed state of the original platen.
0), document size detecting means (reflection type document size detection sensor 105 shown in FIG. 8) for detecting an image document placed on the platen glass at a predetermined position on the platen glass,
On the basis of the result of detecting the open / close state of the document pressure plate by the pressure plate state detection means, the control unit controls the driving of the irradiation unit, the image reading unit, and the document size detection unit to execute an image document size detection sequence and read the image. Control means (controller 110 shown in FIG. 8) for controlling the image signal detected by the means to amplify the detected image signal and the detection result of the document size detection means when the image document size detection sequence is executed. Determining means for determining the size of a document placed on the platen glass based on the document (the controller 110 shown in FIG. 8)
And

According to a second aspect of the present invention, there is provided a pressure plate state detecting means for detecting when the original platen is opened (FIG. 2).
2) and a sensor (photo sensor 113 shown in FIG. 2) for detecting when the original pressure plate is closed.
The open / closed state of the original document pressure plate is detected by using one of these.

According to a third aspect of the present invention, the pressure plate state detecting means includes one double-action sensor (photosensor 112 shown in FIG. 2) for detecting when the document pressure plate is opened and when the document pressure plate is closed. To detect the open / closed state of the original pressure plate.

According to a fourth aspect of the present invention, there is provided an analog-to-digital converter (A / D converter 706 shown in FIG. 8) for converting an analog image signal output from the image reader into a digital signal. The control unit includes an image output from the image reading unit that is input to the determination unit when the platen state detection unit detects that the original platen is open or that the original platen is closed. The signal is amplified before being converted to digital by the analog-to-digital conversion means (the gain of the variable amplifier of the AP-IC 704 shown in FIG.
control 705).

According to a fifth aspect of the present invention, there is provided an analog-to-digital converter (A / D converter shown in FIG. 8) for converting an analog image signal output from the image reader into a digital signal based on a set input range. D converter 706), and the control means controls the input range of the analog-to-digital conversion means when the pressure plate state detection means detects that the original pressure plate is open or the original pressure plate is closed. (The input range of the A / D converter 706 shown in FIG. 10 is set to Vref-c).
control by the control unit 806) to amplify the image signal output from the image reading unit and input to the determination unit.

According to a sixth aspect of the present invention, the control means multiplies the image signal input to the determination means by a previously obtained correction coefficient only when the image document size is detected.

According to a seventh aspect of the present invention, the control means controls the switching of the image document size detection sequence based on the open / close state of the document pressure plate detected by the pressure plate state detection means.

According to an eighth aspect of the present invention, in the document feeder (document shown in FIG. 1), the document pressing plate is configured to sequentially feed a plurality of documents placed on a document placing table onto the platen glass. Feeding device 115).

According to a ninth aspect of the present invention, the pressure plate state detecting means is provided at a portion near a mounting position of the document pressure plate.

According to a tenth aspect of the present invention, there is provided an original platen glass on which an image original is set, and an openable and closable unit which presses the image original set on the original platen glass so as not to float on the original platen glass. Document pressing plate, irradiation means for irradiating light to the image document placed on the platen glass,
A reading unit for inputting reflected light from the image original by irradiation of the irradiation unit, reading the image original, and outputting an image signal;
Pressure plate state detection step of detecting the open state and the closed state of the document pressure plate (steps S1102 and S1104 in FIG. 12)
A document that controls the driving of the irradiating means and the image reading means to execute an image document size detection sequence based on the result of detecting the open / close state of the document pressing plate, and amplifies an image signal detected by the image reading means; Size detection step (Steps S1103 and S110 in FIG. 12)
5, S1109) and a judging step of judging the size of a document placed on the platen glass based on the detection result of the amplified detected image signal when the image document size detection sequence is executed (FIG. 12). Step S1106).

According to an eleventh aspect of the present invention, an original platen glass on which an image original is set and an image original set on the original platen glass can be opened and closed by pressing the original platen glass so as not to float. Document pressing plate, irradiation means for irradiating light to the image document placed on the platen glass,
A reading plate for detecting an open state and a closed state of the document pressing plate, the reading device comprising: reading means for reading reflected image from the image document by the irradiation of the irradiation means and reading the image document and outputting an image signal; State detection step (FIG. 12)
Steps S1102 and S1104), based on the detection result of the open / close state of the document pressure plate, controls the driving of the irradiating unit and the image reading unit to execute an image document size detection sequence, and performs detection by the image reading unit. Document size detection step for amplifying image signals (FIG. 1)
(Steps S1103, S1105, S1109 of 2)
And a judging step of judging the size of the original placed on the platen glass based on the detection result of the amplified detected image signal when the image original size detection sequence is executed (Step S1106 in FIG. 12). Is stored in a storage medium so that the program can be executed by a computer.

[0024]

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

FIG. 1 is a sectional view illustrating the structure of an image forming apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 115 denotes a document feeder which sequentially feeds the documents stacked on the document feeder one by one onto the glass platen glass 111. The document feeder 115 also serves as an openable and closable document pressure plate for pressing a document set on a document table glass 111 on which an image document is set so as not to float on the document table glass 111. .

Reference numeral 103 denotes a first mirror table unit which includes a document irradiation light source 707 and a mirror,
The lamp 103 is turned on while moving the upper original surface to illuminate the entire original surface.

The mirror in the first mirror base unit 103, the second mirror base unit 104, and the lens input the reflected light from the original to the CCD unit 102.

The CCD unit 102 photoelectrically converts the reflected light of the irradiated document and outputs an electric signal. Reference numeral 110 denotes a controller which converts an electric signal photoelectrically converted by the CCD unit 102 into a digital image and performs image processing set by various operation units. The controller 110
An external switching circuit (not shown) includes an image reading unit 10.
A selector is provided for switching the signal from 1 to the image output device 712 or an external device (not shown). Further, the controller 110 includes a CPU, ROM, RA (not shown).
M, etc., and the CPU performs overall control of the entire image forming apparatus based on a program stored in a ROM (not shown) or another storage medium.

Next, in the image output device 712, 20
Reference numeral 1 denotes an exposure control unit which modulates an electric signal input from the controller 110 of the image reading unit 101 to the image output device 712 to convert the electric signal into an optical signal, and irradiates the photosensitive member 202 with the light.
A latent image is formed on the photoconductor 202.

A developing unit 203 develops a latent image formed on the photosensitive member 202 by irradiation light with a developer such as toner. Reference numeral 206 denotes a transfer unit which transfers a developer image on the photoconductor 202 developed by the developing unit 203 from the transfer paper stacking unit 204 or the transfer paper stacking unit 205 in synchronization with the leading end of the developer image. Transfer to paper.

A fixing unit 207 fixes the developer image transferred by the transfer unit 206 on transfer paper. A paper discharge unit 208 discharges the fixed transfer paper to the outside of the apparatus. The paper discharge unit 208 is reversible and can be reversed.
The transfer paper conveyed up to can be reversely conveyed. A conveyance direction switching member 209 guides the sheet reversely conveyed by the sheet discharge unit 208 to the transfer sheet stacking unit 210 for re-feeding. A sorter 220 has a plurality of bins, and discharges the transfer paper output from the paper discharge unit 208 to the outside of the apparatus to each bin.

The operation of each section will be described below.

The originals stacked on the original feeder 115 are sequentially conveyed onto the original glass 111 one by one. When the original is transported to a predetermined position on the glass platen 111, the first
The original irradiating light source 707 of the mirror base unit 103 is turned on, and the first mirror base unit 103 moves to illuminate the original.

The reflected light of the original is transmitted to the first mirror base unit 1
The data is input to the CCD unit 102 via the mirror in the mirror 03, the mirror in the second mirror base unit 104, and the lens.
The reflected light of the document irradiated on the CCD unit 102 is photoelectrically converted here, and the converted electric signal is sent to the controller 110. The controller 110 performs image processing set by various operation units.

The electric signal output from the controller 110 to the image output device 712 is converted into an optical signal modulated by the exposure control unit 201 and irradiates the photosensitive member 202. The latent image formed on the photoconductor 202 by the irradiation light is developed by the developing device 203.

The transfer paper is conveyed from the transfer paper stacking unit 204 or the transfer paper stacking unit 205 in synchronization with the timing of the above-mentioned development, and the developed image is transferred to the transfer unit 206. The transferred image is fixed on the transfer paper by a fixing unit 207, and then discharged outside the apparatus from a paper discharge unit 208. The transfer paper output from the paper output unit 208 is
Emitted at 0.

Next, a method of outputting sequentially read images on both sides of one output sheet will be described.

After the output sheet fixed by the fixing unit 207 is once conveyed to the sheet discharging unit 208, the sheet conveyance direction is reversed, and the transfer sheet stack unit 210 for re-feeding the sheet via the conveyance direction switching member 209. Transport to When the next manuscript is prepared,
The original image is read in the same manner as in the above process, but the transfer paper is fed from the re-feeding receiving paper stacking section 210, so that two original images are output on the front and back surfaces of the same output paper. can do.

Although FIG. 1 shows the case where the image output device 712 is of the electrophotographic type, the present invention can be applied to an ink jet type, a sublimation type, a thermal transfer type and other types.

FIG. 2 is a diagram showing the configuration of the image reading unit 101 of the image forming apparatus shown in FIG. 1, and the same components as those in FIG. 1 are denoted by the same reference numerals.

In the figure, (a) corresponds to a configuration diagram of the image reading unit viewed from directly above, (b) corresponds to a configuration diagram of the image reading unit viewed from the front, and (c) corresponds to a document pressing plate. This corresponds to a side view showing the opening and closing state.

Hereinafter, the document size detecting operation of the image forming apparatus of the present invention will be described.

In this description, for simplicity, a description will be given of a case in which a white plate type having no document feeding function (document feeding device 115) is used as the document pressing plate. The same operation is performed when this is used.

In FIGS. 7A and 7B, reference numeral 107 denotes a document pressure plate (hereinafter, referred to as a pressure plate) which can be opened and closed. The document pressure plate 107 is used for pressing a document against the platen glass 111 to prevent the document from floating.

In the image forming apparatus, when an original is set on the image reading apparatus, an operation of opening the pressure plate 107, setting the image original on the glass platen 111, and closing the pressure plate 107 is involved.

At this time, the pressure plate 107 is connected to a pressure plate detection switch (SW) 1 provided near the position where the pressure plate is mounted.
06 is pressed, and the state of the pressure plate can always be detected under the same conditions regardless of the type of the document pressure plate, depending on how the pressure plate detection SW 106 is pressed.

Reference numeral 105 denotes a reflection type original size detection sensor.
The original placed on the platen glass 111 is transferred to the platen glass 11
A predetermined light is radiated at a predetermined position and the reflected light is input to detect the original, and is used to determine the size of the image original in the sub-scanning direction.

In (c), reference numerals 112 and 113 denote photosensors for detecting the pressure plate detection SW 106, which are configured at positions where the pressure plate 107 can detect the pressure plate closed state (pressure plate open state) and the pressure plate closed state. .

Also, as shown at 114, the shape of the pressure plate detection switch is devised, and 114-
By forming a hole such as 1,114-2, a similar effect (a pressure plate open / closed state detection light or the like) can be provided even when only one photo sensor 112 is used as a double action sensor. At this time, the hole 114-
1 detects that the pressure plate is almost closed (open state of the pressure plate);
-2 is used to detect the pressure plate closed state.

Reference numeral 710 denotes a pressure plate state detection sensor, which is a photosensor 112, a photosensor 113 and a pressure plate detection SW 106, or a photo sensor 112 and a pressure plate detection SW1.
The pressure plate 107 detects the pressure plate open state and the pressure plate closed state of the pressure plate 107.

When an image original is set on the glass platen 111 of the image reading apparatus 101 and the platen 107 is in a state of being closed, a state detection signal (closed state signal) is output from the photo sensor 112 and the controller 110 is input. On the controller 110 side, the document irradiation light source 707 set above the first mirror base unit 103 is controlled to be turned on in accordance with the state detection, and the reflection type document size detection sensor 105 is controlled to a detectable state. The width is accurately read using a CCD image sensor (hereinafter, referred to as a CCD), and the sub-scanning direction of the image document is determined by using the reflection type document size detection sensor 105 to determine whether the document is a long document.

The above-mentioned CCD is incorporated in the CCD unit 102, and the light emitted from the first mirror base unit 103 is reflected by the original (not shown) through the second mirror base unit 104 to read the reflected light. In the reading state with the pressure plate released, only the light in the document area is read. At this time, differences in detection results as shown in FIGS. 3 and 4 described later occur depending on the luminance density of the document image.

FIG. 3 is a diagram showing a document reading example (white document reading example) when the luminance density of the image document is high.
Examples of this type of manuscript include general office documents and weekly magazines.

FIG. 4 is a diagram showing an original reading example (black original reading example) when the luminance density of the image original is low. This type of original is similar to the original sheet of the second original. , Paper types with high transparency, and documents with solid black on the entire surface.

Hereinafter, an original detection method for each original type (white original and black original) will be described with reference to FIGS.

First, when reading the original size of a white original with the pressure plate released, an image is read at a level as in the example shown in FIG.

This means that the document irradiating light source 707 is turned on in synchronization with the output of the pressure plate state detecting sensor 710, that the main scanning data of the irradiated image document is sampled, and that the reflection type document size detecting sensor 105 In particular, FIG. 3A shows CC of the original width reading line.
The D output signal level is shown. At this time, since there is almost no return light in the area outside the original, the CCD output is at a negligible level. Similarly, FIG.
As shown in FIG. 5, when the pressure plate is completely closed, the area outside the document is also read in white.

A method for detecting the main scanning width of the document size from the document reading level is, for example, a method as shown in FIG.

In this figure, A and B are document width detection points, respectively, which are document width detection points set inside the fixed size document width in a state where the documents are abutted. The document width detection point is constituted by a data string composed of a predetermined number of pixels, and for example, determination is made based on whether the average value of the read values for 64 pixels or 128 pixels is larger or smaller than the document determination threshold. .

Incidentally, in an image reading apparatus that reads at a resolution of 600 dpi, the reading width for a document is:
64 pixels correspond to an area of about 2.7 mm, and 128 pixels correspond to an area of about 5.4 mm. In this case, the determination result can be determined as follows. In the figure, C is a reflection type original size detection sensor 1.
It is assumed that the reading point is 05, and the judgment result at each point is "1": document is present, and "0": no document is present. When the pressure plate is opened: A ... "1", B ... "0", C ... "0" When the pressure plate is closed: A ... "1", B ... "1", C ... "1" At this time, the detection level of A is Although unchanged, the detection level of B has changed, and it is recognized that the document width is up to the point of A. As shown in C, the reflection-type original size detection sensor 105 that cannot be detected when the pressure plate is opened, is detected when the pressure plate is closed, and is a pressure plate.

Accordingly, in the case shown in FIG. 3 described above, it is determined that the original size is such that a fixed original whose main scanning length is up to A and whose sub-scanning does not reach C is detected.

Next, when reading the size of the black document with the pressure plate released, the image is read at a reading level as shown in the example of FIG.

In this example, the level of the image read by the CCD is extremely low, and is around 10 levels at an 8-bit resolution (about 1.38 in luminance density). The non-document area is, in effect, a non-reflection area of the document irradiation light, at the same level as the optical black (light-shielding portion) of the CCD, and has a reading value near one level.

Similarly, in the example shown in FIG. 4 (b), the white pressure plate is read for the area outside the document, while the document area remains unchanged.

In this state, the determination result is determined as follows, as in the example of FIG. The determination results at points A, B, and C are "1": the document is present, and "0": the document is not present. When the pressure plate is open: A ... "0", B ... "0", C ... "0" When the pressure plate is closed: A ... "0", B ... "1", C ... "1" At this time, the detection level of A is Although unchanged, the detection level of B has changed, and it is recognized that the document width is up to the point of A. As shown in C, the reflection-type original size detection sensor 105 that cannot be detected when the pressure plate is opened, is detected when the pressure plate is closed, and is a pressure plate.

Based on this, it is determined that the original size is such that a fixed original whose main scanning length is up to A and sub-scanning does not reach C is detected.

The above-described fixed-size original will now be described with reference to FIGS. 5, 6, and 7. FIG.

The fixed document sizes generally used in the image forming apparatus include the document types shown in FIGS.

In the image forming apparatus, an AB system (A3, A4, A
5 ..., B4, B5, ...) and inch type (STMT, LET)
It is general to set the detected original size separately for TER, LEGAL... This is due to the fact that the paper size used differs depending on the region.

FIGS. 5 to 7 are diagrams showing fixed size originals and reading positions in the image forming apparatus of the present invention.

The difference between the example shown in FIG. 5 and the example shown in FIG. 6 is that the first mirror base unit 1 when detecting the document size is used.
This indicates that the number of reflective document size detection sensors 105 in the sub-scanning direction is different due to the difference in position 03 and the position of the first mirror base unit 103.

Here, an example of the AB system shown in FIG. 5 will be described.

The reading position for detecting the original main scanning width is
Since it is located at a position 20 mm from the image destination, the main scanning width is the same paper type, that is, (A5 size and A4R size) or (B
5 size and B4 size), (A4 size and A3 size)
244mm from the image
It is necessary to arrange the reflection type document size detection sensor at the position of the position.

By the way, at the position of 330 mm from the image tip,
A5 size and A4R size cannot be distinguished.

Similarly, the example of the inch system shown in FIG. 5 will be described. As can be seen from the drawing, the paper types having the same main scanning width are as follows. (STMT, LETTER_R and LEGAL), (LE
(TTER and LEDGER) Here, there are three types of paper having the same main scanning width, and a 2-bit signal is required to separate the three types.

In order to discriminate the inch type paper,
The reflection type document size detection sensor 105 is set at a position of about 244 mm from the image tip and at a position of about 330 mm, respectively, and the following detection is performed. STMT: 244 mm sensor ... 0, 330 mm sensor ... 0 LETTER_R: 244 mm sensor ... 1, 330 mm sensor ... 0 LEGAL: 244 mm sensor ... 1, 330 mm sensor ... 1 From these detection results, the inch paper type Can be determined.

Next, as shown in FIG. 6, the position of the first mirror base unit 103 for reading the original main scanning width is set at one position from the image tip.
A description will be given of document size detection when the size is set to 60 mm.

In the AB system shown in FIG. 6, an A5 size document width cannot be read at this reading position.

However, by using the reflection type original size detection sensor 105 set at a position of 330 mm from the image tip, the paper types (B5 and B4) and (A4 and A3) can be determined. Similarly, considering the inch system shown in FIG. 6 with exactly the same configuration, paper types other than STMT can be similarly detected. With the configuration shown in FIG. 6, paper types other than A5 and STMT can be detected with exactly the same configuration without using a destination-specific configuration, and global document size detection can be performed.

Next, as shown in FIG. 7, a reading position (detection configuration 2) different from the above-described main scanning reading position (20 mm from the image destination: detection configuration 1, 160 mm from the image destination: detection configuration 3), that is, 140mm to 148m from the tip
When the first mirror base unit 103 is set between m and the reflection type original size detection sensor 105 is set near 290 mm from the image tip, all paper types other than STMT can be detected.

Although the document width reading position and the discrimination paper type have been described, as described above, at each document size determination point ABC, a portion where the determination result does not change when the pressure plate is opened or closed indicates the size of the document. . This is because the reading level of the area where the original is loaded is not affected by the pressure plate.

However, in actuality, with respect to transparent paper types such as the second original drawing paper, there are also problems such as the case where the influence of the pressure plate cannot be ignored and the case where the luminance density of the document is too low to exceed the threshold value. . It can live. In order to eliminate such an erroneous determination factor of the document size detection and increase the determination accuracy, the following method is adopted to increase the accuracy of the document size detection.

FIG. 8 is a block diagram showing a first control configuration of the image forming apparatus according to the present invention, which is a configuration utilizing the configuration of a normal image reading apparatus as it is. 1 and 2
The same components as those described above are denoted by the same reference numerals.

The configuration and operation will be described below.

In the figure, reference numeral 701 denotes a CCD for reading an original. Normally, by pressing a copy button on an operation panel (not shown), the controller 110 turns on the document irradiation light source (light source) 707 and scans the image document (not shown) to read the image document. CCD 701
Then, the input optical signal is converted into an electric signal and output, and is connected to an anapro IC (AP-IC) 704 via an emitter follower 702 and an AC coupling capacitor 703.

Inside the Anapro IC 704, the A /
There is a mechanism for adjusting (amplifying) the signal level so as to match the input range of the D converter 706. Normally, the brightness level of SK paper or DK paper serving as a white reference of the image forming apparatus is set to F0.
(H) light source 707 and Anapro IC7
The gain of the variable amplifier 04 is adjusted.

With this adjustment, adjustment is performed by the A / D converter 706 so that the white portion of the image document becomes FF (H) and the black portion becomes 00 (H), and the document reading unit is adjusted to the optimum setting. Note that this adjustment includes light distribution correction of the light source, sensitivity unevenness correction of the CCD, and the like.

The original image read by the reading system adjusted as described above is converted into a video signal by the image processing unit 709, sent to the image output device 712, and printed out.

When this series of flows is applied to document size detection, after an image document is set on a document table glass 111 (not shown), when an output signal of the pressure plate state detection sensor 710 comes in, the controller 110 controls the document irradiation light source. 70
7 and the ON control of the reflection type document size detection sensor 105 is prompted.

At this time, since the pressure plate is in the closed state, the area outside the document is in a non-reflective input state. In this state, several lines of line data are sampled at regular intervals, and when a signal is input from the platen state detection sensor 710, several lines of line data in the platen closed state are sampled, and the detection result remains unchanged. The document size is detected using the result of the determination.

Here, when an original having a luminance density of about 1.38 is read by the CCD 701, the read value is about 10 levels at 8 bits, and it is difficult to determine that the read value of the light-shielding section is about 4 levels. . Therefore, at the moment when the document size is detected, that is, while the detection result is output from the pressure plate state detection sensor 710, the VCA-
By adjusting the control signal 705, the circuit gain is increased, and the document size detection capability is enhanced. FIG. 9 shows the relationship between the circuit gain and the image data at this time.

FIG. 9 is a characteristic diagram showing an example of the relationship between the circuit gain set at the time of detecting the document size and the read image level in the image forming apparatus of the present invention. The horizontal axis corresponds to the set circuit gain. The vertical axis corresponds to the read image level.

Normally, the circuit gain is set by a predetermined set value so that the reading level of a blank sheet becomes FF (H), that is, the input range of the A / D converter.

At this time, when the input range of the A / D converter is set at 2 V from 1 V (Vbottm) to 3 V (Vtop), the read value T of a predetermined document is 80 (H) = 1.
28 (DEC).

An analog processing IC 7 is provided for this image processing system so that the circuit gain becomes 1.5 times when the document size is detected.
When the setting for adjusting the VCA-control signal 705 set to 04 is performed, the read value T1 becomes C0 (H) = 192 (DEC).

In this image processing system, the data determination level Kd (the threshold for determining the presence or absence of a document) is temporarily set to AA (H).
= 170 (DEC), T (80 (H) = 128 (DEC)) read with normal circuit gain setting
Cannot be determined, but T1 (C0 (H) = 192 (DEC)) read with the circuit gain increased can be determined.

As described above, it can be easily determined that the determination accuracy can be improved by increasing the circuit gain.

As a method of controlling the circuit gain,
The same effect can be obtained even if the input range is narrowed by controlling the Vtop of the A / D converter.

FIG. 10 shows this example.

FIG. 10 is a block diagram showing a second control configuration of the image forming apparatus according to the present invention, which is a configuration utilizing the configuration of a normal image reading apparatus as it is. Note that the same components as those in FIG. 8 are denoted by the same reference numerals.

As shown, the CCD output 701 is A
Anapro I via C coupling condenser 703
The signal is input to C704, amplified to a signal level suitable for the input range of A / D converter 706, and output. A / D
The output of the converter 706 is converted into a video signal by the image processing unit 709 inside the controller 110 and output to the image output device 712.

With this configuration, the illumination of the original irradiating light source 707 is controlled in synchronization with the output signal from the pressure plate state detecting sensor 710, and at the same time, the reflection type original size detecting sensor 105 is turned on.
Control is performed.

Further, when the Vref-control signal 806 input to the A / D converter 706 is controlled to lower the potential level, the input range of the A / D converter 706 is reduced, and the input signal to the A / D converter 706 is reduced. An operation is performed as if the conversion result was amplified.

For example, suppose that the input range of the normal A / D converter 706 is 2 V, and Vbottm = 1 V
And Vtop = 3V, and this 2V range is 8 bits.
, The input signal of 2V level is 80 (H) = 128 (DEC).
If Vtop = 2V, the video signal is FF
(H) = 256 (DEC), which means that the signal was amplified twice.

However, in this case, since the input range is narrowed with respect to the noise component included in the input signal of the A / D converter, the S / N characteristic is deteriorated by the half of the dynamic range. This description is shown below in FIG.

FIG. 11 is a characteristic diagram showing the relationship between the Vtop potential set in the A / D converter 706 and the reading level when the document size is detected in the image forming apparatus of the present invention, and the vertical axis indicates the A / D converter 706. Vt to be set
The horizontal axis corresponds to the read image level, corresponding to the op potential.

In this figure, from Vref1 to Vref3,
Vtop voltages of 3 V, 2.5 V and 2 V are set in the A / D converter 706, respectively, and A / D at the Vtop potential is
9 shows a change in the read value T2 with respect to the A / D input of the D converter 706. Vref1: 80 (H) ... T2: 128 (DEC) Vref2: AA (H) ... T2: 170 (DEC) Vref3: FF (H) ... T2: 255 (DEC) Thus, the A / D converter 706 has Vtop. A / D converter reference voltage Vref for setting potential
Is lowered to Vref3 to Vref1 to perform an operation as if the circuit gain was increased.

When the circuit gain control method described above with reference to FIGS. 8 to 11 is detected, that is, when the original platen is opened or the original platen is closed,
By adjusting the gain of the variable amplifier of Anapro IC704,
A method of adjusting the circuit gain of the image processing system by amplifying the detection signal before it is converted into a video signal (digital signal), or a state in which the original platen is opened or a state in which the original platen is closed Is detected, A /
By controlling the reference voltage of the D converter 706 and using a technique for adjusting the circuit gain of the image processing system at the time of detecting the document size, the document size detection device set to the threshold value of about 30 (H) allows the luminance density 1 .38 (about 10 levels) multiplied by a gain of about 4 times makes it possible to enhance the document detection capability.

At this time, the light-shielding part level is about four levels, and even when the gain is multiplied, the level of the document (4
(Approximately 40 levels when the gain is multiplied by about twice).

This method is used at the time of document size detection. When the document detection is completed, the circuit gain returns to the initial appropriate setting, and prepares for reading of the image document.

[0112] Further, it is often observed when a Book original is copied. When a book is set on a glass platen and the copy button is pressed without closing the pressure plate, the circuit gain and the original are synchronized with the copy button. The lighting control of the irradiation light source and the drive control of the reflection type document size detection sensor are performed, and the document size is determined from the read data of several lines at that time.

However, since the circuit gain of the present invention can discriminate a document having a low luminance density and can detect even a highly transparent second original sheet or the like, the same result as when the pressure plate is opened and closed can be detected. It is possible to provide the detection accuracy of

Hereinafter, an example of the document size detection processing in the image forming apparatus of the present invention will be described with reference to the flowchart of FIG.

FIG. 12 is a flowchart showing a first control processing procedure of the image forming apparatus of the present invention, and corresponds to an example of a document size detection processing. Note that S1101 to S111
0 indicates each step, and the processing of this flowchart is as follows.
It is assumed that a CPU (not shown) in the controller 110 shown in FIG. 1 executes based on a program stored in a ROM (not shown) or another storage medium.

In step S1101, an image original is set. In step S1102, it is determined whether the pressure plate 111 is in the closed state. If it is determined that the pressure plate 111 is not in the closed state, step S1108 is performed. If the copy button has not been pressed (ON), the process returns to step S1102. On the other hand, if the copy button has been pressed, the process proceeds to step S1109, where lighting control of the document irradiation light source, circuit gain UP, and reflection type document size sensor have been performed. In step S1106, original size detection (determination) is performed based on the sampling data at that time (the size detection result in step S1109). When the document size is determined, step S
In step 1107, an original image is read and an image is formed.

On the other hand, in step S1102, the pressure plate 111
Is determined to be in the closed state, the process proceeds to step S
Proceeding to 1103, lighting control of the document irradiating light source, circuit gain UP, drive control of the reflection type document size sensor are performed, and the detection result at that time is sampled.
Go to 04.

In step S1104, it is determined whether or not the pressure plate has been completely closed. If it is determined that the pressure plate has not been completely closed, in step S1110, it is determined whether or not the copy button has been pressed (ON). Do
If it is determined that the copy button has not been pressed (ON), the process returns to step S1104. On the other hand, if it has been determined that the copy button has been pressed (ON), in step S1106, the process returns from the size detection result of step S1103. The document size is detected (determined), and step S
In step 1107, an original image is read and an image is formed.

On the other hand, if it is determined in step S1104 that the pressure plate has been completely closed, the process proceeds to step S1104.
At 105, lighting control of the document irradiating light source, circuit gain UP, and drive control of the reflection type document size sensor are performed. At step S1106, the document size detection with higher accuracy from the size detection result at step S1103 and the size detection result at step S1105 is performed. (Determination), and in step S1107, an original image is read and an image is formed.

As described above, the CPU (not shown) of the controller 110 generates the size detection start signal of the image document based on the result of the state determination of the document platen 111 by the platen state detection sensor 710, and the light source 707, the CCD 701,
By controlling the drive of the reflection type document size detection sensor 105 and adjusting the circuit gain of the image processing system,
The detection accuracy of document size detection can be improved.

As described above, in order to always detect the state of the pressure plate under the same conditions irrespective of the type of the original pressure plate, the state of the pressure plate as shown in FIG. By providing a sensor, a detection result under the same condition can be obtained without being affected by the types of the pressure plate and the document feeding device.

Further, in order to realize a high original size detection capability even for an original having a low luminance density of an image original, the original size detection signal is multiplied by a predetermined amplification factor, and a detection sequence according to the state of the pressure plate is performed. The detection accuracy can be improved by providing the image document (switching the detection sequence of the image document according to the state of the document pressure plate).

In the above-described embodiment, the variable gain of the AP-IC 704 is used as a means for adjusting the circuit gain of the image processing system when the state where the original platen is opened or the state where the original platen is closed is detected. A method of amplifying a detection signal before it is converted into a video signal (digital signal) by the A / D converter 706 by adjusting an amplification factor of the amplifier, or a circuit gain by controlling a reference voltage of the A / D converter 706. The case where the detectable original luminance density range is expanded by using the method of adjusting the
Alternatively, the image processing unit 709 uses a safety factor (correction coefficient) obtained in advance for the video signal and multiplies the video signal only when the image document size is detected, so that the detectable document luminance density range is expanded. You may comprise.

The image forming apparatus to which the present invention can be applied may be an electrophotographic type, an ink jet type, a sublimation type, a thermal transfer type, or another type.

In the above embodiment, the case where the present invention is applied to the image forming apparatus has been described. However, an original image placed on an original platen glass is read, and a predetermined communication medium (Ethernet (registered trademark) or the like) is read. Network and U
The present invention may be applied to an image reading device (not provided with an image forming function) for outputting to an external device such as a computer via an interface such as an SB or SCSI, or for storing in a predetermined storage means such as a hard disk. Needless to say.

As described above, according to the present invention, an original having a low luminance density or an original illuminating light, which can be read only at a level which is difficult to detect when the pressure plate is opened, is transmitted, resulting in a low read value. This has the effect of increasing the document size detection capability for the document. As a result, even if the original is a Book copy with the pressure plate released and the original sheet is the second original drawing, the original size is correctly detected and an appropriate image reading operation is performed.
A copying operation can be performed.

Hereinafter, the configuration of a data processing program that can be read by the image forming apparatus according to the present invention will be described with reference to a memory map shown in FIG.

FIG. 13 is a view for explaining a memory map of a storage medium for storing various data processing programs which can be read by the image forming apparatus according to the present invention.

Although not shown, information for managing a group of programs stored in the storage medium, for example, version information, a creator, etc. is also stored, and information dependent on the OS or the like on the program reading side, for example, a program is stored in the storage medium. An icon or the like for identification display may also be stored.

Further, data dependent on various programs is also managed in the directory. Also, if the programs and data to be installed are compressed,
A program for decompressing may also be stored.

The functions shown in FIG. 12 in this embodiment may be performed by a host computer by a program installed from the outside. In this case, the present invention is applied even when a group of information including a program is supplied to the output device from a storage medium such as a CD-ROM, a flash memory, or an FD, or from an external storage medium via a network. Things.

As described above, the storage medium storing the program codes of the software for realizing the functions of the above-described embodiments is supplied to the system or the apparatus, and the computer (or CPU or MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, C
D-ROM, CD-R, DVD-ROM, magnetic tape,
A non-volatile memory card, ROM, EEPROM, silicon disk, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) And the like perform part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. .

Further, by downloading and reading out a program represented by software for achieving the present invention from a database on a network using a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

[0139]

As described above, the first embodiment according to the present invention is described.
According to the present invention, the image document placed on the platen glass is illuminated on the basis of the result of detecting the open / close state of the document pressure plate by the pressure plate state detection means provided near the document pressure plate mounting position. Irradiating means, reading means for inputting reflected light from an image document by irradiation of the irradiating means, reading the image document and outputting an image signal, and reading the image document placed on the platen glass into the document table. While controlling the drive of the document size detecting means for detecting at a predetermined position of the glass, and executing the image document size detection sequence,
The detection image signal by the image reading means is controlled so as to be amplified, and when the detection sequence is executed, the detection image signal is placed on the document table based on the amplified detection image signal and the detection result of the document size detection means. Since the size of the document is determined, the document size detection ability can be read only to a level that is difficult to detect when the pressure plate is released. Can be enhanced,
The detection result under the same condition can be obtained without being affected by the types of the pressure plate and the document feeding device.

Accordingly, it is possible to improve the document size detection capability for a document having a low luminance density or a document whose reading value is reduced due to transmission of document irradiation light, which can be read only to a level which is difficult to detect when the pressure plate is opened. It is possible to obtain the same detection result under the same conditions without being affected by the type of the pressing plate and the document feeding device. This has the effect that the original size can be correctly detected and a proper copying operation can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of an image reading unit of the image forming apparatus illustrated in FIG.

FIG. 3 is a diagram illustrating a document reading example (white document reading example) when the luminance density of an image document is high.

FIG. 4 is a diagram illustrating a document reading example (black document reading example) when the luminance density of an image document is low.

FIG. 5 is a diagram illustrating a fixed-size document and a reading position in the image forming apparatus of the present invention.

FIG. 6 is a diagram illustrating a fixed-size document and a reading position in the image forming apparatus of the present invention.

FIG. 7 is a diagram illustrating a fixed-size document and a reading position in the image forming apparatus of the present invention.

FIG. 8 is a block diagram illustrating a first control configuration of the image forming apparatus of the present invention.

FIG. 9 is a characteristic diagram showing an example of a relationship between a circuit gain set at the time of detecting a document size and a read image level in the image forming apparatus of the present invention.

FIG. 10 is a block diagram illustrating a second control configuration of the image forming apparatus of the present invention.

FIG. 11 is a characteristic diagram illustrating a relationship between a Vtop potential set in an A / D converter and a reading level when a document size is detected in the image forming apparatus of the present invention.

FIG. 12 is a flowchart illustrating a first control processing procedure of the image forming apparatus of the present invention.

FIG. 13 is a diagram illustrating a memory map of a storage medium that stores various data processing programs that can be read by the image forming apparatus according to the present invention.

[Explanation of symbols]

 105 Reflection type document size detection sensor 106 Pressure plate detection switch (SW) 107 Document pressure plate 111 Platen glass 112 Photosensor 113 Photosensor 114 Pressure plate detection switch (SW) 701 CCD 707 Light source 704 AP-IC 705 VCA-control signal 706 A / D converter 110 Controller 710 Pressure plate state detection sensor 806 Vref-control signal

Claims (11)

[Claims] 1. An original platen glass on which an image original is set, an openable and closable original platen for pressing an image original set on the original platen glass so as not to float on the original platen glass, and the original platen glass Irradiating means for irradiating light on the image document placed thereon, and reading means for inputting reflected light from the image document by irradiation of the irradiating means, reading the image document, and outputting an image signal A pressure plate state detecting means for detecting an open state and a closed state of the document pressure plate; and a document size detection for detecting an image document placed on the platen glass at a predetermined position on the platen glass. Means for controlling the driving of the irradiating means, the image reading means, and the document size detecting means on the basis of the result of detecting the open / close state of the document pressing plate by the pressure plate state detecting means. Control means for executing a document size detection sequence and controlling to amplify the image signal detected by the image reading means; and when the image document size detection sequence is executed, the amplified detected image signal and the document size detection means Determining means for determining the size of a document placed on the platen glass based on the detection result of the image forming apparatus. 2. The pressure plate state detecting means detects the open / close state of the pressure plate using two sensors, one for detecting when the document pressure plate is open and the other for detecting when the document pressure plate is closed. The image forming apparatus according to claim 1. 3. The pressure plate state detecting means detects the open / close state of the document pressure plate using one double-action sensor that detects when the document pressure plate is opened and when the document pressure plate is closed. Item 2. The image forming apparatus according to Item 1. 4. An analog-to-digital converter for converting an analog image signal output from the image reading unit into a digital signal, wherein the control unit determines whether the platen state detecting unit is in a state where the original platen is opened or When detecting a state in which the document pressure plate is closed, an image signal output from the image reading unit and input to the determination unit is amplified before being converted into a digital signal by the analog-to-digital conversion unit. The image forming apparatus according to claim 1. 5. An analog-to-digital converter for converting an analog image signal output by the image reader into a digital signal based on a set input range, wherein the control means includes a pressure plate state detecting means, When detecting the state where the original platen is opened or the state where the original platen is closed, the image reading unit which is input to the determination unit by changing and controlling the input range of the analog-to-digital conversion unit is output. The image forming apparatus according to claim 1, wherein the image signal is amplified. 6. The apparatus according to claim 1, wherein said control means multiplies the image signal input to said determination means only by a correction coefficient obtained in advance when the image document size is detected. An image forming apparatus according to claim 1. 7. The apparatus according to claim 6, wherein the control unit is configured to determine whether the original platen is open or closed based on the state of the original platen detected by the platen state detection unit.
The image forming apparatus according to any one of claims 1 to 6, wherein switching of the image document size detection sequence is controlled. 8. A document feeding device according to claim 1, wherein said document pressing plate includes a document feeding device for sequentially feeding a plurality of documents placed on a document table onto said glass table glass. An image forming apparatus according to any one of the above. 9. An image forming apparatus according to claim 1, wherein said pressure plate state detecting means is provided at a portion near a mounting position of said document pressure plate. 10. An original platen glass on which an image original is set, an openable and closable original platen for pressing an image original set on the original platen glass so as not to float on the original platen glass, and the original platen glass Irradiating means for irradiating light on the image document placed thereon, and reading means for inputting reflected light from the image document by irradiation of the irradiating means, reading the image document, and outputting an image signal A pressure plate state detecting step of detecting an open state and a closed state of the document pressure plate; and driving the irradiation unit and the image reading unit based on a result of detecting the open / close state of the document platen. A document size detecting step of controlling and executing an image document size detection sequence, and amplifying a detected image signal by the image reading means; A determination step of determining a size of a document placed on the platen glass based on a detection result of the amplified detection image signal during a detection sequence;
A method for controlling an image forming apparatus, comprising: 11. An original platen glass for setting an image original, an openable and closable original platen for pressing an image original set on the original platen glass so as not to float on the original platen glass, and the original platen glass Irradiating means for irradiating light on the image document placed thereon, and reading means for inputting reflected light from the image document by irradiation of the irradiating means, reading the image document, and outputting an image signal A pressure plate state detecting step of detecting an open state and a closed state of the document pressure plate, and controlling the driving of the irradiation unit and the image reading unit based on a result of detecting the open / close state of the document platen. A document size detection step of executing an image document size detection sequence and amplifying a detection image signal by the image reading means; At the time of the determination, a determination step of determining the size of the document placed on the platen glass based on the detection result of the amplified detection image signal,
A storage medium storing a computer-readable program for executing the program.