JP4353825B2 - Image reading method and apparatus, and image forming apparatus using the same - Google Patents

Description

The present invention feeds a series of original sheets stacked on a stacker one by one to the platen one by one, and when reading an image on the sheet with this platen, two or more sheets are stacked and sent to the platen. The present invention relates to an image reading method and apparatus that detects and efficiently processes this.

Generally, a series of sheets stacked on a stacker are separated and fed one after another and conveyed to a platen. An image reading apparatus that optically reads an image on the sheet with a photoelectric conversion element and outputs it as electronic data with this platen is a scanner or copying machine. Widely used in facsimiles and the like. The sheet fed from the stacker to the platen by such an apparatus needs to take measures to stop the apparatus by detecting an abnormality such as a paper jam in the course of conveyance with a sensor. Conventionally, a so-called jam processing in which a sensor such as a photodiode is provided in the sheet conveyance path to detect a paper jam (jam), the apparatus is stopped, and the operator recovers is used in many apparatuses.

In addition to the above-described jam processing, for example, Japanese Patent Application Laid-Open No. H10-228707 proposes a technique that detects the double feeding of two or more sheets fed from the stacker and stops the apparatus. This is a separating means that separates the stacker sheets and may feed out two or more sheets. If this is read with the platen, the read data will be missing, and the user will not notice this problem. In order to do this, the document 1 described above detects the overlap of two or more sheets, stops the apparatus, returns the overlapped sheet to the stacker again, and continues reading thereafter.

In addition, an ultrasonic sensor is widely used for detection of double feeding of a sheet, and a pulse voltage having a predetermined frequency is applied to the piezoelectric vibrator, and the ultrasonic wave passing through the sheet is detected by the piezoelectric vibrator. It is known to discriminate whether there is one sheet or plural sheets from ultrasonic energy attenuated. When such multi-sheet feeding occurs, the conveyance of the sheet is stopped in the same manner as when a paper jam (jam) occurs, and the multi-feed sheets are removed from the apparatus and the order is arranged again on the stacker. It is set and supplied.
Japanese Utility Model Publication No. 6-49567 Japanese Patent Laid-Open No. 10-257595

However, even if the double feed detection means such as an ultrasonic sensor detects the double feed of the sheet, if the operator stops the apparatus and waits for the operator's correction work when it is detected as in the prior art, the operator When the user is away from the device, the apparatus must wait for a long time and the work efficiency becomes worse.

The present inventor has come to the knowledge that, unlike paper jams, sheets can be conveyed and read as they are in the overlapped state. Therefore, according to the present invention, the overlap of the sheets is detected by the double feed detecting means in the process of feeding the sheets from the stacker to the platen, and when the sheets are fed, a series of sheets are read without omission without requiring user maintenance. An object of the present invention is to provide an image reading method and an apparatus capable of reading the image.

The present invention employs the following configuration in order to achieve the above-described problems.
First, an image reading apparatus according to the present invention is an apparatus for reading an image on an original sheet by sequentially feeding original sheets having a series of page attributes from a stacker to a reading platen, and a stacker on which a series of original sheets are placed. Two or more originals disposed between the stacker and the reading platen, an image reading means for reading an image on the original sheet with the reading platen, a data storage means for storing image data read by the image reading means, and Double feed detecting means for detecting sheet overlap, page order determining means for determining the feeding order of the original sheets sent to the reading platen, information from the double feed detecting means, and information from the page order determining means The multi-feed page storage means for storing the page order of the multi-fed original sheets based on the above and the control means for the image reading means .

The control means includes a first reading mode in which image data of all sheets are stored in the data storage means in a sending order with respect to an original sheet sent to the reading platen, and only image data of the selected sheet is stored. Is stored in the data storage means. In the second reading mode, a series of original sheets placed again on the stacker after the execution of the first reading mode is read. When passing through the platen, only the image data of the document sheets of the feed order stored in the multi-feed page storage unit is stored in the data storage unit .

Next, an image reading method of the present invention is an image reading method for reading an image on a document sheet by sequentially feeding document sheets having a series of page attributes from a stacker to a reading platen, and a series of the sheets placed on the stacker. Document feed step for sequentially feeding the original sheets to the reading platen on the downstream side, a double feed detection step for detecting overlap conveyance of the document sheets from the stacker to the reading platen, and a double feed detection step. A multi-feed page storing step for discriminating and storing the feeding order of the manuscript sheets, and a manuscript re-sending step for placing a series of sheets on the stacker and retransmitting them to the reading platen after reading the series of manuscript sheets, Of the original sheets passing through the reading platen in the original re-sending step, the feeding order stored in the multi-feed page storing step A second data storage step of storing image data, and a data output step of outputting the first and the image data stored in the second storing step to the outside in the order of page attributes.

In the present invention, the double feed detection of the sheet fed from the stacker to the reading platen and the sheet feed order are discriminated, and the feed order of the double fed sheet is identified. You can know if there is a double feed. Therefore, if the feeding order of the multi-fed sheets is displayed on the operation panel or the like, it is easy for the user to correct the missing reading data. Also, the feeding order of the multi-fed sheets is stored and the missing readings are made by re-reading the multi-fed sheets. It is also possible to supplement the data. Further, it is possible to store the feeding order of the multi-feed sheets, feed a series of sheets again from the stacker to the reading platen, and read and complement the image of the previously fed multi-sheet.

As described above, the present invention is an image reading method capable of efficiently performing an operation without stopping the apparatus even when multiple feeding of sheets occurs in a process of sequentially reading a series of sheets, and thereafter easily supplementing missing data. And an apparatus can be provided.

The present invention will be described in detail below based on the preferred embodiments shown in the drawings.
In the present invention, when a series of originals are sequentially separated from a stacker and supplied to an image reading platen of an image forming apparatus such as a scanner or a printer or a copying machine, two or more originals are supplied in a superimposed manner. This is detected in the middle of conveyance so that it can be processed without missing in subsequent image formation. FIG. 1 is an explanatory diagram modeling each mechanism of an image forming apparatus that supplies a series of documents from a stacker to a reading platen (hereinafter referred to as a platen) and prints an image read by the platen. FIG. 4 is a block diagram showing the control circuit, and FIG. 4 is a flowchart showing the operation procedure.

In FIG. 1, A indicates an image reading apparatus, and B indicates an image forming apparatus. The image reading apparatus A includes a feeder unit A1 that supplies a document to the platen, and a scanner unit A2 that reads the document on the platen by a photoelectric conversion unit, and the image forming apparatus B prints on the sheet feeding unit B1 that supplies a print sheet and the sheet. A printing unit B2 for performing the above and an image data control unit B3 for sending image data to the print head. The feeder unit A1 includes a paper feed stacker 101 for placing originals, a separation unit 102 for separating the originals on the paper feed stacker 101 one by one, and a conveyance path 104 for guiding the originals from the separation unit 102 to the platen 103. , A paper discharge stacker 105 for storing documents from the platen 103 is provided. The conveyance path 104 is formed in a substantially U shape, and the paper feed stacker 101 and the paper discharge stacker 105 are arranged above and below the platen 103 in parallel. Further, a registration roller 106 that temporarily waits for a document and a feed roller 107 that supplies the document from the registration roller 106 to the platen 103 are arranged in this order on the conveyance path 104, and the document is located downstream of the platen 103. Is provided with a paper discharge roller 108.

Therefore, a multi-feed detection unit 109 for detecting the sheet overlap state and a sheet edge detection sensor 110 for detecting the leading edge of the document are arranged between the separating unit 102 and the registration roller 106. As will be described later, the double feed detection means 109 is, for example, an ultrasonic sensor in which the oscillation element 109a and the vibration receiving element 109b are arranged to face each other via a document, and whether there is a single document sent with the attenuation amount of the ultrasonic wave passing through the document It is detected whether two or more sheets are overlapped. The sheet edge detection sensor 110, for example, arranges a light-emitting element and a light-receiving element of a photo sensor facing each other through a document, detects the presence or absence of the document, and detects the arrival of the document tip. The illustrated separating means 102 includes a separating roller 102a for feeding the uppermost document on the paper feed stacker 101 and a friction pad 102b. Various separating means 102 are known and any of them can be adopted. . Reference numeral 111 denotes a pickup roller that feeds a document on the sheet feed stacker 101 toward the separation roller 102a. 112 is a lead sensor that detects the leading edge of the document, detects the timing at which the leading edge of the document has arrived, and determines the reading start line on the platen 103.

The pickup roller 111, the separation roller 102a, and the registration roller 106 are coupled to a drive motor (not shown) so as to rotate in a reciprocal manner, and the registration roller 106 stops when the pickup roller 111 and the separation roller 102a rotate. When the registration roller 106 rotates, the pickup roller 111 and the separation roller 102a are configured to stop. Accordingly, the document fed out by the pickup roller 111 and the separation roller 102a hits the stopped registration roller 106 to draw a curved loop, and when the document is fed to the platen 103 by the registration roller 106, the pickup roller 111 and the separation roller 102a are stopped. This prevents the subsequent document from being pulled out. In this case, the pickup roller 111 may stand by at a position retracted from the document.

The scanner unit A2 includes a photoelectric conversion unit 120 for reading a document moving on the platen 103, a data processing circuit 121 for correcting the read data, and a data transfer circuit 122 for transferring the data to the image forming apparatus B. The photoelectric conversion means 120 irradiates the original on the platen 103 with light from the light source, forms an image on a photoelectric conversion element such as a CCD through a lens, and converts the image on the original as an electrical signal. Various other photoelectric conversion means 120 are known and any of them can be used. The data processing circuit 121 and the data transfer circuit 122 will be described later. The data processing circuit 121 performs A / D conversion on an electrical signal (analog signal) from the photoelectric conversion element, and performs line correction, shading correction, gamma correction, and the like. After performing the correction process, the data transfer circuit 122 transfers the data stored in the buffer memory to the image forming apparatus B via the interface 160.

Next, the image forming apparatus B is configured to sequentially feed the print sheets stored in the paper feeding unit B1 to the printing unit B2, form an image in the printing unit B2, and discharge the printed sheet to the stacker 157. The sheet feeding unit B1 stores print sheets in one or a plurality of sheet feeding cassettes 150, separates them one by one by a sheet feeding roller, and sends them to the registration rollers 152 from the carry-out conveyance path 151. Then, the printing timing is adjusted and supplied to the printing unit B2. For example, the printing unit B2 irradiates the electrostatic drum 153 with light with a print head 154 such as a laser oscillator, applies toner ink with a developing device (not shown), and transfers the toner ink onto a sheet with a charger 155. Reference numeral 156 shown in the figure denotes a fixing device that heats and fixes the ink on the sheet. The sheets on which images are formed in this manner are sequentially stacked and stored in the stacker 157. As the print head 154, various printing means such as an ink jet head and a dot impact head can be employed in addition to a laser oscillator.

The image data sent from the scanner unit A2 is sent to the image data control unit B3 via the interface 160, and the image data control unit B3 includes a data storage device 158 such as a hard disk and a print control circuit 159. . Therefore, the control CPU 123 of the image reading apparatus A shown in FIG. 2 receives the signals from the sheet end detection sensor 110 and the double feed detection means 109 and the discharge sensor 113 disposed at the positions of the lead sensor 112 and the discharge roller 108. The signal is transmitted. Further, an instruction signal for starting image reading is transmitted to the control CPU 123 from a start button 124 provided on the control panel. The control CPU 123 calls the image reading program 125 from the ROM, executes reading control, corrects the read data, which will be described later, and then stores the data in the data storage device 158.

Therefore, the number of ON signals of the read sensor 112 or the paper discharge sensor 113 arranged on the sheet conveyance path transmitted from the control CPU 123 to the feeder unit A1 is measured by a counter 127 constituted by a RAM or a CPU register. At this time, if the double feed detecting means 109 is ON, 1 is added to the count value of the counter.

When image data is stored in the data storage device 158 of the image forming apparatus, the page number (counter value) is also stored together as additional information (header information or the like). The page number at this time is missing because the double-fed page is not stored. After the reading operation is completed, if there is data in the multi-feed page memory 130, the discharged document is set on the tray again in the order of page numbers, so that the images are read in ascending order of the page numbers of the multi-feed sheets. At this time, the page number of the double feed page memory is sequentially added to the read image data and stored in the data storage device 158. The CPU manages all addresses where image data and additional information are stored. When printing, the CPU issues a command to print in order starting from page number 1 of the additional information.

Simultaneously with the operation of the start button 124 of the image reading apparatus A, the multi-feed processing is selected. (See FIG. 2) This multi-feeding process selects a continuous reading mode and a warning stop mode, which will be described later, and the continuous reading mode (Process 1) is a multi-feed display process (Process A1) and a multi-feed original re-feed ( Either processing A2) or re-feeding all documents (processing A3) is set, or the user selects from a plurality of processes each time.

Therefore, when the reading start start button 124 is operated (ST01), the document on the paper feed stacker 101 is fed out from the top sheet and separated (ST02). In this separation and feeding, for example, as described later, the pickup motor 111 and the separation roller 102a are rotated by rotating the drive motor M in response to a signal that the empty sensor on the stacker detects the presence of paper. The document is separated by the separating unit 102 and reaches the registration roller 106. In response to the paper feed instruction signal, the registration roller 106 is activated and rotated to feed the original toward the platen 103. In this process, it is detected by the double feed detecting means 109 whether or not one document or a plurality of documents are overlapped. This double feed detection will be described later.

As a result of the double feed detection (ST03), if it is identified as one sheet, the document is read by the platen 103 and carried to the paper discharge stacker 105 by the paper discharge roller 108 (ST09). On the other hand, if it is determined that two or more originals overlap, the process proceeds to the set multi-feed process.

When the selected process is in the continuous reading mode, the multi-feed page order is stored (ST05). If the signal from the double feed detecting means 109 is compared with a reference value to determine double feed, the counter 127 determines the feed order of the documents fed from the stacker. The page order discriminating means constituted by the counter 127 is initialized by the operation of the start button 124, counts the number of ON signals of the read sensor 112 or the paper discharge sensor 113, and stores the count value in a storage means such as a RAM. The apparatus shown in the figure rarely overlaps three or more original sheets. Therefore, when double feeding is detected, all the sheets are processed as two (double feed). When discriminating the number of sheets, the sheet discharge sensor value and the number of sheets fed double are also stored. For example, (n), (n + 1) is stored when the nth document is determined to be double feed, or (n), (n + 1)... (N + (k−1) when the double feed number is k. )) Is stored (ST05). Next, the count value of the counter 127 is also counted up (ST07). On the other hand, the document sheet determined to be double-fed is discarded without passing through the platen 103 without reading the image with the platen 103 or without sending the read data to the data processing unit.

The original that has passed through the platen 103 is carried out to the paper discharge stacker 105, and the original is detected by the paper discharge sensor 113. The signal from the paper discharge sensor 113 is counted by the counter 127 (ST08). When the next original is on the paper feed stacker 101 (when the empty sensor is ON), the process returns to the original separation and feeding step (ST02), and such an operation is repeated. When the multi-feed page order is not stored in the multi-feed page memory 130 at the stage where reading of a series of documents is completed, the image forming process is executed based on the data stored in the data storage device 158 of the image data control unit B3. The

On the other hand, when the multi-feed page order is stored in the multi-feed page memory 130, one of the following processes 1, 2, and 3 is executed.
[Process 1]
The page stored in the double feed page memory 130 is displayed on the display unit 128 of the control panel. Based on this display, the user pulls out the document that has been fed and is not read from the document on the paper discharge stacker 105, sets it again on the paper feed stacker 101, and presses the start button 124. As a result, the above-described steps are executed again, and image formation is performed. Therefore, the user collates the copy sheets and arranges the page order to finish the work.
[Process 2]
The page stored in the double feed page memory 130 is displayed on the display unit 128 of the control panel. Simultaneously with this display, the “multi-feed page re-feed” guidance is displayed. Based on this guidance, the user “sets a document that has not been read by double feeding from the documents taken out from the paper discharge stacker 105 to the paper feed stacker 101 and presses the start button 124”. Then, this document is read in the same procedure as described above.
[Process 3]
Guidance “Reset original” is displayed on the display unit 128 of the control panel (see ST24 in FIG. 5). The user sets a series of originals again on the paper feed stacker 101 and presses the start button 124 (ST27). Then, the original is separated and fed by the separating means 102 and sent toward the platen 103 (ST28). This document collates whether the count value obtained by counting the sheet feed instruction signal by the counter 127 matches the page order read from the previous multi-feed page memory 130 (ST29). If they match in this collation, that is, the document that has not been read by double feeding in the previous reading, the image is read (ST32) through the detection of the double feed detecting means 109 (ST30).
If it is determined that the feed is double feed, the drive motor M is stopped and a warning to the effect of double feed is displayed on the display unit. In response to this warning, the user takes out the document stopped in the multi-feed conveyance path 104, resets it on the paper feed stacker 101, and presses the start button 124 to restart.
A document read by the platen 103 without being double-fed is carried to the paper discharge stacker 105 by the paper discharge roller 108 (ST36, ST37).
Documents that do not match the page order in collation (ST29) are ejected (ST36) without executing image reading because they have been read. At this time, when the double feed detecting means 109 determines that double feed is performed (ST33), the counter 127 is incremented by 1 (ST34), and further counted up at ST35 and discharged (ST36).
The data read in this way is processed as follows.

Here, double feed detection will be described. FIGS. 7 and 8 show a case where an ultrasonic sensor is adopted as the double feed detection means 109, FIG. 7 shows its structure, and FIG. 8 shows a discrimination circuit. In a normal ultrasonic sensor, the transmitting element 109a and the receiving element 109b are composed of elements having the same structure, and a piezoelectric vibrating body 11 such as a piezoelectric ceramic plate is embedded in an elastic resin 12 in a case 10 made of metal or the like. It is. Electrodes are formed on the front and back surfaces of the piezoelectric vibrator 11 by vapor deposition, and a high frequency power is supplied from the lead wire 13. Further, the illustrated piezoelectric vibrator 11 is in close contact with the outer casing 10 and vibrates at a specific frequency based on the natural frequency in which both are integrated, and the wave transmitting surface 10a forming a part of the case. Ultrasonic waves are transmitted to the outside. One of the lead wires 13 is grounded to the outer casing case 10.

Accordingly, when a high frequency power is supplied from the lead wire 13 on the wave transmitting element 109a side, the piezoelectric vibrating body 11 and the outer casing case 10 in contact with the vibrating body 11 vibrate at a predetermined frequency and emit ultrasonic waves from the wave transmitting surface 10a. On the other hand, the wave receiving element 109b resonates by the ultrasonic wave received by the wave receiving surface 10b of the outer casing case 10 and the piezoelectric vibrating body 11 integrated therewith, and the electricity generated in the piezoelectric vibrating body 11 passes through the lead wire 13 from the electrode. Output to the outside.

The ultrasonic sensor having such a structure is arranged in the conveyance path 104 and connected to the oscillation circuit 14 and the vibration receiving circuit 15 as shown in FIG. The oscillation circuit 14 includes a high frequency oscillation circuit 14a and an amplification circuit 14b, and supplies a high frequency voltage having a specific frequency from the power source 14c to the piezoelectric vibrating body 11. The vibration receiving circuit 15 is composed of an amplifier circuit 15a composed of a transistor or the like and a smoothing circuit 15b. The high-frequency oscillation circuit 14 a generates a high-frequency voltage of, for example, 30 KHz to 400 KHz, amplifies this signal, and applies it to the electrodes formed on the front and back of the piezoelectric vibration body 11 from the lead wire 13 to excite the piezoelectric vibration body 11. This ultrasonic wave excites the piezoelectric vibrating body 11 on the receiving element side through the sheet and is output as an electrical signal. The output signal from the wave receiving element 109b is amplified by the amplifier circuit 15a, rectified by the smoothing circuit 15b, and smoothed by the integrating circuit or the like.

Therefore, when power is supplied to the high-frequency oscillation circuit 14a, ultrasonic vibration of a specific frequency is excited by the piezoelectric vibrating body 11 of the transmission element 109a. As shown in FIG. 7A, the piezoelectric vibrating body 11 emits ultrasonic waves at a high frequency with a constant amplitude (output level LV1). The receiving element 109b facing the transmitting element 109a receives the ultrasonic wave through the sheet, the piezoelectric vibrating body 11 on the receiving element 109b side resonates, and the electric power generated by the vibration is output. At this time, the attenuation of the ultrasonic wave when passing through the sheet is different from the output when there is one sheet (output level LV2) and the same two sheets (c) (output level LV3) as shown in FIG. 7B. Become.

The electric energy output in the waveforms of FIGS. 5B and 5C is processed by the amplifier circuit 15a and the smoothing circuit 15b. That is, the electric energy of the vibration waveform output from the wave receiving element 109b is amplified and then rectified and converted to an output level as shown in FIGS. 7D and 7E by the smoothing circuit 15b formed of an integrating circuit. FIG. 4D shows the output level LV2 when the sheet is conveyed by one sheet, and the detection value of the portion A is disturbed with the leading edge of the sheet reaching the sensor position from the registration rollers 106a and 106b. This is because the leading edge of the sheet flutters because the sheet is fed out by the registration roller 106 from a state in which the sheet is curved in a loop shape. In section B, the detected value is stable when the sheet is nipped by the registration roller 106 and along the conveyance path 104, and in section C, the detection value is obtained when the rear end of the sheet is separated from the registration rollers 106a and 106b (passes the roller position). Is disturbed. FIG. 7 (e) shows the output level LV3 when two sheets are conveyed while being overlapped, and the A part, the B part, and the C part respectively show the above-described states.

Therefore, when the reference value is set to the level LV0 indicated by the dotted line in the figure, the relationship of LV1> LV2> LV0> LV3 is established in the stable B portion between one sheet (d) and two sheets (e). . Accordingly, when the output signal from the smoothing circuit 15b is compared with the reference value (LV0) by the comparison circuit (means) 15c such as a comparator in the B part, it is possible to determine the sheet overlap state. In determining the reference value, first, conditions such as sheet thickness, paper quality, and conveyance speed are determined based on the use environment of the apparatus. Under these conditions, when one sheet is used and two sheets are determined by experiments. Obtain the boundary value of the output level of the receiving sensor at the time and set this value as the reference value.

The reference values have been described for the case of one sheet and two or more sheets. However, a plurality of reference values are set such as when there are one sheet, two sheets, and more, and each is compared. By doing so, it is possible to detect how many sheets overlap. Either high-frequency voltage is instantaneously applied from the high-frequency oscillation circuit 14a to the transmission element 109a to generate a burst wave, or power is continuously applied to generate a stationary wave. In this case, since the output from the wave receiving element 109b is unstable (easy to change due to environmental conditions) in the overlapping state of the sheets, it is preferable to detect the burst wave repeatedly repeatedly intermittently.

Next, the arrangement of the ultrasonic sensor having the above-described structure will be described. The wave transmitting element 109a and the wave receiving element 109b are arranged as follows with respect to the sheet conveyance path 104.

The wave transmitting element 109a and the wave receiving element 109b are arranged so as to face each other while being inclined by a predetermined angle with respect to a sheet traveling on the conveyance path 104. As shown in FIG. 7, it is inclined at an angle α with respect to a perpendicular line NN perpendicular to the transport path, and in the illustrated one, the angle α is set to 30 degrees to 45 degrees. This is because the ultrasonic wave oscillated from the transmission element 109a is reflected on the sheet surface and returns to the surface (transmission surface) of the transmission element 109a to avoid the oscillation wave and the reflected wave. It avoids occurring between the wave receiving surface 10b of the wave element 109b. Therefore, the angle α may be set according to the distance between the sheet and the surface of the transmission (receiving) wave and the area of the surface of the transmitting (receiving) wave. (2) A transmitting element is arranged on the lower side and a receiving element on the upper side in the direction of gravity with respect to the transport path 104. As described above, the intensity of vibration (LV1) generated on the transmission surface of the transmission element 109a is larger than that of the reception element 109b. At the same time, in order to discriminate the difference in the level of resonance (vibration intensity) that occurs on the receiving surface when the sheets are overlapped with each other, the external influence on the receiving surface is reduced. There is a need. Therefore, by arranging the wave transmitting element 109a on the lower side where the gravity acts and the wave receiving element 109b on the upper side, the influence of paper dust and other dust falling from the sheet conveyance path on the detection accuracy is reduced. (3) The transmission surface 10a of the transmission element 109a arranged further below is arranged so as to be inclined at a predetermined angle (β) with respect to the horizontal direction. The angle β is selected so that dust falls naturally from the surface or falls in cooperation with ultrasonic vibration. In the illustrated example, this angle β is set to 30 degrees, and it is needless to say that this angle is preferably close to 90 degrees.

Next, details when the present invention is adopted in the image forming apparatus will be described with reference to FIGS. FIG. 9 shows an overall configuration of an image forming apparatus B provided with the image reading apparatus A. The image forming apparatus B includes a casing 162 in which a printing drum 153, a paper feed cassette 150 that supplies paper to the printing drum 153, a developing device 160 that develops and forms toner ink on the printing drum 153, and a fixing device 156. ing. Reference numeral 154 denotes a print head such as a laser that forms a latent image on the print drum 153. The paper from the paper feed cassette 150 is sent to the print drum 153 by the transport roller 161, and the image formed by the print head 154 is transferred. This sheet is fixed by the fixing unit 156 and is stored in the sheet discharge stacker 157 from the sheet discharge roller 163. Such an image forming apparatus B is widely known as a printer, and includes a paper feeding unit, a printing unit, and a paper discharge storage unit. Each functional unit is not limited to the above-described structure, and various types such as ink jet printing and silk screen printing are employed. Is possible.

The print head 154 is electrically connected to a data storage device 158 such as a hard disk for storing image data and a print control circuit 159 for sequentially transferring the stored image data to the print head. Above the image forming apparatus B, an image reading apparatus A is attached as a unit. In this image reading apparatus A, a platen 103 is attached to a casing 136, and a photoelectric conversion means 120 and a photoelectric conversion element 124 for reading a document sheet via the platen are arranged. A CCD or the like is widely known as the photoelectric conversion element 124.

A feeder unit A1 shown in FIG. In the feeder unit A1, a sheet feed stacker 101 and a sheet discharge stacker 105 are arranged above and below the platen 103, and a sheet from the sheet feed stacker 101 passes through the platen 103 through a U-shaped conveyance path 104. Guide to the paper discharge stacker 105. The paper feed stacker 101 is provided with an empty sensor 117 and a size sensor (not shown) for detecting the presence or absence of a placed sheet, and 133 shown in the figure is a side guide for regulating the side edge of the sheet.

A separation roller 102a and a friction pad 102b pressed against the separation roller 102a are disposed on the upstream side of the paper feed stacker 101, and a pickup roller 111 is attached to a bracket 119 attached to the rotating shaft 102c of the separation roller 102a. When the rotating shaft 102c is rotated clockwise, the pickup roller 111 is lowered onto the paper feed stacker 101, and when the rotating shaft 102c is rotated counterclockwise, the pickup roller 111 is raised to the state shown in the drawing, but the mechanism will be described later. . An ultrasonic sensor 109 that detects the overlapping state of sheets and a sheet end detection sensor 110 that detects the leading and trailing edges of the sheet are disposed in the conveyance path 104 on the downstream side of the separation roller 102a. In addition, registration rollers 106a and 106b, feed rollers 107a and 107b, carry-out rollers 129a and 129b, and paper discharge rollers 108a and 108b are sequentially provided in the conveyance path 104 in this order. These rollers convey the sheet from the paper feed stacker 101 to the paper discharge stacker 105. 112 is a lead sensor for detecting the leading edge of the sheet. Reference numeral 131 denotes a circulation path in which the sheet from the platen 103 is retransmitted to the registration rollers 106a and 106b by the path switching gate 131a.

Next, FIG. 11A shows a drive mechanism for the separation roller 102a and the registration roller 106b, and shows a transmission mechanism for driving the pickup roller 111, the separation roller 102a, and the registration roller 106b by a paper feed drive motor 140 capable of forward and reverse rotation. FIG. 11B shows a transmission mechanism that drives the feeding roller 107, the carry-out roller 129, and the paper discharge roller 108 by the conveyance drive motor 141. The paper feed drive motor 140 rotates the pickup roller 111 and the separation roller 102a in the forward direction, and rotates the registration roller 106 in the reverse direction. At the same time, the paper feed drive motor 140 controls the pickup roller 111 to move up and down. The paper feed drive motor 140 transmits only rotation in one direction to the registration roller 106 by the one-way clutch 142 via the belts B1 and B2. At the same time, the paper feed drive motor 140 is connected to the rotating shaft of the separation roller 102a by a one-way clutch 143, and is set so that the one-way clutches 142 and 143 transmit driving in a reciprocal manner.

A bracket 119 is supported on the rotating shaft of the separation roller 102a via a spring clutch 144, and the drive is transmitted to the pickup roller 111 attached to the bracket 119 by the transmission belt B3. When the paper feed drive motor 140 is rotated forward, the separation roller 102a and the pickup roller 111 are rotationally driven. At the same time, the spring clutch 144 is loosened and the bracket 119 becomes free, and the pickup roller 111 is lowered from the raised retracted position in FIG. Touches the sheet on the stacker. When the paper feed drive motor 140 is rotated in the reverse direction, the drive is transmitted to the registration roller 106b, and at the same time, the spring clutch 144 is tightened to raise the bracket 119 and return it to the retracted position in FIG.

As shown in FIG. 11B, the transport drive motor 141 is connected to the feed roller 107, the carry-out roller 129, and the paper discharge roller 108 via belts B5, B6, and B7, and the feed roller 107, the carry-out roller 129, and the like. The one-way clutch always rotates in one direction regardless of whether the motor is rotating forward or backward, and the paper discharge roller 108 is rotated forward or backward by the motor.

Next, a sensor for detecting the arrival of the leading edge of the sheet is arranged in the conveyance path 104, and the operation thereof will be described. A plurality of size sensors (not shown) for detecting the prescribed size of the set sheet are arranged on the sheet feed stacker 101, and the subsequent sheet conveyance is controlled by detecting the sheet size. An empty sensor 117 that detects the presence or absence of a sheet on the stacker is provided at the leading end of the sheet feed stacker 101, detects the feeding of the final sheet, and sends a signal to a processing apparatus such as the image reading apparatus A. The ultrasonic sensor 109 and the sheet end detection sensor 110 described above are provided on the downstream side of the separation roller 102a.

  A lead sensor 112 is provided in front of the feeding roller 107 to notify the image reader of the arrival of the leading edge of the sheet and to determine the starting line of image reading and printing. At the same time, if a sheet is not detected even after a predetermined time has elapsed since the rotation of the registration roller 106 is started, the drive motor is stopped as a jam and a warning signal is issued at the same time. A paper discharge sensor 113 is disposed on the downstream side of the carry-out roller 129, and detects the leading edge and the trailing edge of the sheet to determine a jam.

Next, the control of the above-described apparatus will be described. The apparatus power is turned on and a sheet (original) is set on the sheet feed stacker 101. With this sheet set, the empty sensor 117 detects the paper presence state and activates the paper feed drive motor 140. Then, the pickup roller 111 descends downward from the state shown in FIG. 10 and feeds the uppermost sheet on the stacker. Next, the fed sheet is separated into one sheet by the separation roller 102a and fed to a conveyance guide between the separation roller 102a and the registration roller 106, and the sheet end detection sensor 110 detects the leading edge of the sheet. The sheet feeding drive motor 140 is stopped after a predetermined time from the detection signal at the leading edge of the sheet. At this time, the sheet is curved in a loop shape with the leading end abutting against the stopped registration roller 106, and when several sheets are overlapped, an air layer is formed between the plurality of sheets.

  Next, the control unit of the image reading apparatus A reversely rotates the paper feed drive motor 140 with a timing signal in which a predetermined interval is formed between the paper feed instruction signal and the main body device such as a computer or the previously fed sheet. Restart in the direction. At the same time, the control unit operates a timer, and this timer is set to an expected time in which the sheet loop is eliminated and the sheet becomes linear between the separation roller 102a and the registration roller 106. FIG. 12C shows a state where the set time of the timer has expired.

  Next, double feeding of the sheet is detected by the ultrasonic sensor 109 until the trailing edge of the sheet is separated from the separation roller 102a in the state of FIG. The leading edge of the sheet is detected by the lead sensor 112 and is fed toward the platen 103 by the feeding roller 107. In this process, when the double feed detecting unit 109 detects double feed of the sheet, the double feed processing of the sheet described with reference to FIGS. 3 and 4 is executed.

In this operation, the sheet end detection sensor 110 detects the sheet leading end in FIG. 12A, and the timer T1 is activated. Next, in the state (b), the leading edge of the sheet hits the registration roller 106 and curves in a loop shape. In this state, the set time of the timer T1 ends and the motor 140 is stopped.

Next, when a paper feed instruction signal is issued from the control unit of the image reading apparatus A, the motor 140 is restarted in the reverse rotation direction. The timer T2 is activated by a paper feed instruction signal. The timer T2 (see FIG. 4) eliminates the registration loop, and the sheet is supported and conveyed linearly between the separation roller 102a and the registration roller 106. This state is shown in FIG. Next, double feeding of the sheet is detected by the ultrasonic sensor 109 until the trailing edge of the sheet is separated from the separation roller 102a in the state of FIG. The trailing edge of the sheet fed in this way is detected by the sheet edge detection sensor 110, and the leading edge of the sheet is detected by the lead sensor 112 before and after the detection of the trailing edge of the sheet, and is directed toward the platen 103 by the feeding roller 107. Are sent.

FIG. 3 is an explanatory diagram modeling each mechanism unit of the image reading apparatus and the image forming apparatus embodying the present invention. The block diagram which shows the control circuit of the apparatus of FIG. Explanatory drawing of a data storage device. The flowchart which shows the operation | movement procedure of the apparatus of FIG. The flowchart which shows the operation | movement procedure of the apparatus of FIG. The flowchart which shows the operation | movement procedure of the apparatus of FIG. Structure explanatory drawing at the time of using an ultrasonic sensor as a double feed detection sensor. FIG. 7 is a control circuit diagram of the ultrasonic sensor of FIG. 6. 1 is an overall explanatory diagram of an image reading apparatus embodying the present invention and an image forming apparatus including the image reading apparatus as a unit; FIG. FIG. 9 is a detailed explanatory diagram of a document sheet supply unit in the apparatus of FIG. 8. Explanatory drawing which shows the drive mechanism of the apparatus of FIG. FIG. 9 is an explanatory diagram of an operation state of sheet supply in the apparatus of FIG.

Explanation of symbols

101 Paper Feed Stacker 102 Separating Means 102a Separating Roller 102b Friction Pad 103 Platen 104 Transport Path 105 Paper Discharge Stacker 106 Registration Roller 107 Feeding Roller 108 Paper Discharge Roller 109 Double Feed Detection Means 110 Sheet Edge Detection Sensor 111 Pickup Roller 112 Lead Sensor 113 Paper discharge sensor 158 Data storage device

Claims (2)

An apparatus for sequentially feeding an original sheet having a series of page attributes from a stacker to a reading platen and reading an image on the original sheet,
A stacker to place a series of document sheets;
Image reading means for reading an image of a document sheet with the reading platen;
Data storage means for storing image data read by the image reading means;
A double feed detecting means disposed between the stacker and the reading platen for detecting an overlap of two or more original sheets;
Page order discriminating means for discriminating the feeding order of the original sheets sent to the reading platen;
Double feed page storage means for storing the page order of the document sheets that are double fed based on the information from the double feed detection means and the information from the page order determination means;
Control means for the image reading means;
With
The control means includes
A first reading mode in which image data of all sheets is stored in the data storage means in the sending order with respect to the original sheet sent to the reading platen, and only the image data of the selected sheet is stored in the data storage means. A second reading mode stored in
Have
In the second reading mode, the feeding order stored in the multi-feed page storage means when a series of document sheets placed on the stacker again passes the reading platen after the execution of the first reading mode. An image reading apparatus configured to store only image data of an original sheet in the data storage means . An image reading method for reading an image on a document sheet by sequentially feeding a document sheet having a series of page attributes from a stacker to a reading platen,
A document conveying step of sequentially feeding a series of document sheets placed on the stacker to a downstream reading platen;
A double feed detecting step for detecting an overlap conveyance of the original sheet from the stacker to the reading platen;
A multi-feed page storing step for determining and storing the feeding order of the document sheets detected in the multi-feed detection step;
After reading a series of document sheets, a document resending step for placing the series of sheets on the stacker and resending to the reading platen;
A second data storage step for storing the image data of the feed order stored in the multi-feed page storage step among the document sheets passing through the reading platen in the document retransmission step;
An image reading method comprising: a data output step of outputting the image data stored in the first and second storage steps to the outside in the order of page attributes .

Images