JP2925142B2 - Image reading device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image reading apparatus of the present invention, and more particularly to an image reading apparatus capable of specifying an image reading area.

2. Description of the Related Art Conventionally, an image reading apparatus selects one of the following two reading ranges based on its specifications.

1. The size of the original to be read 2. The reading area specified by the external device Normally, in the original moving image reading apparatus 120 shown in FIG. When the reading of the document conveyed by the conveyance mechanism 122 is completed, the transmission of the image information ends.

On the other hand, a moving image reading apparatus of a reading optical system shown in FIG.
At 110, the second method is adopted, and a reading area is designated with reference to an original area designation index 112 provided around the original glass 111. When a reading area larger than the original is designated, the original pressure plate surface 113 provided on the original cover 114 is provided.
Is read and becomes a margin.

[Problems to be Solved by the Invention] However, the conventional example has the following problems.

In the case where image information transmission is terminated based on the size of the document, the amount of image information is determined only after reading the document, so that functions such as resolution selection and enlargement / reduction are not fully utilized.

On the other hand, when reading the designated reading area, it is not easy to know the dimensions of the document to be read and appropriately designate the reading area. Then, after the reading is completed, unless the read image is output once on the CRT or the printer print, it is impossible to know whether or not the specified reading area is appropriate.

[Means for Solving the Problems] The present invention has been made in view of the above points, and has as its object to enable an image reading area designated by an external device to be efficiently read. Moving means for moving a document set on a paper portion to a discharge portion via a document reading position, a light source for exposing the document moving to the document reading position, and an image of the document exposed by the light source for one. A reading element for reading each line, an output means for outputting an image signal read by the reading element to an external device, a means for specifying an image reading area from the external device, a movement of a document by the moving means, and a light source Control means for controlling the exposure of the document, wherein the control means controls the movement of the document by the moving means and the lighting of the light source in accordance with a document reading request from the external device. Image reading which starts, turns off the light source in response to the end of reading of the image reading area specified by the external device by the specifying means, and ends the movement of the original by the moving means after the original has passed the original reading position. An apparatus is provided.

Embodiment (Embodiment 1) FIGS. 1 to 5 show a first embodiment of the present invention.

FIG. 1 is a block diagram of an embodiment of an image reading apparatus to which the present invention is applied, and FIG. 2 is a block diagram showing a circuit configuration of a main part of the image reading apparatus. In FIG. 1, reference numeral 100 denotes an image reading apparatus main body, and reference numeral 200 denotes an automatic feeder (ADF) for feeding a sheet document. 1 is a light source for illuminating the original, 2 and 3
Reference numeral denotes a reading optical system for forming an image on the CCD 4 of light reflected by the document, and is reciprocated in the directions of arrows B and F by a stepping motor (not shown). No. 4, a plurality of light receiving elements for converting the luminance of the original into an electric signal are arranged in lines in the main scanning direction
CCD, reference numeral 5 denotes an original platen glass for supporting a book original, reference numeral 6 denotes a discharge tray, reference numeral 7 denotes a paper feed tray, and reference numeral 8 denotes a separation / feed roller for feeding only one sheet of original on the paper supply tray 7 in the A direction. ,
9 is a platen roller for feeding the fed document to the reading device 50 and supporting the document; 10 is a paper presence / absence sensor for detecting the document on the paper feed tray 7; A feed sensor 12 for detecting the leading and trailing edges of the original; a discharge sensor 12 for detecting the leading and trailing edges of the read original; and a discharge roller 13 for feeding the original onto the output tray 6. is there.

In FIG. 2, reference numeral 20 denotes an image processing circuit 23 which converts an analog signal output from the CCD 4 into a digital signal for each pixel.
A / D converter for sending to the CCD, 21 is a CCD drive circuit for driving the CCD 4, 22 is the A / D converter 20, CCD drive circuit 21, image processing circuit 23,
A timing signal generating circuit 23 for synchronizing the I / F circuit 25 and the CPU 26 with each other, subjects the digital signal output from the A / D converter 20 to various processing, and performs binarization, AE, enlargement,
An image processing circuit for performing image processing such as reduction and inversion, 24 is a line memory for temporarily storing a read image and synchronizing with an external device 31 connected to the present image reading device, 25 is a command for the external device 31 and a command, An interface circuit for communicating status and image information; 26, a CPU for controlling the entire apparatus;
Is the main body stepping motor that moves the reading optical systems 2 and 3,
8 is a motor drive circuit for driving the main body stepping motor 28, 29 is an ADF stepping motor for sending an original on the ADF 200, 30 is a motor drive circuit for driving the ADF stepping motor 29, and 31 is a host to which the image reading device is connected. And an external device such as a computer device or a printer device.

Next, the operation of the above configuration will be described step by step according to the timing charts of FIGS. 3 and 4 and the flow chart of FIG.

The external device 31 outputs a document reading request to the image reading device after specifying a reading designation area (hereinafter referred to as a window) 52 and a reading end condition (hereinafter referred to as a mode). However, one of the following three types can be selected as the mode.

(1) Sheet mode: When the window 52 is larger than the document 53 (FIG. 3), image information of the entire area of the window 52 is transmitted. An image transfer end signal (ACK signal) is sent at the end of the halfway original. On the other hand, when the document 53 is larger than the window 52 (FIG. 4), the transmission of the image information is stopped simultaneously with the end of the document, and the ACK signal is transmitted.

(2) Window mode: Regardless of the end of the scanned document,
Image information of the entire area of the window 52 is transmitted, and an ACK signal is transmitted at the end of the window.

(3) Window second mode: Image information of the entire area of the window 52 is transmitted regardless of the end of the read document. Manuscript 53
When the window 52 is larger than the window 52 (FIG. 3), the AC is performed once each at the end of the read document and at the end of the window.
Send K signal. On the other hand, if the document 53 is larger than the window 52 (FIG. 4), two ac
k is transmitted, and the transmission of the image information ends.

The image reading apparatus that has received the document reading request proceeds to the following operation.

First, the document reading conditions are inspected by the ADF 200 (step 101). If the ADF cannot be used, the document on the document table 5 is read (step 102). If the ADF can be used, the positions of the reading optical systems 2 and 3 are set to the first position. Illustrated
Move to the ADF reading position (steps 103 and 104). After the movement, the stepping motor 29 in the ADF 200 is driven to feed the original 53 on the paper feed tray 7 (step 105). Feed sensor 1
Feed paper until 1 detects the leading edge of the original (Step 10
6,107) If it is detected (Tsφ in Figs. 3 and 4), A
The original is fed by the length ls line (FIG. 1) up to the DF reading position 50 (step 108). Here, the light source 1 is turned on (step 109), the line counter for counting the number of read lines is reset to φ (step 110), and the counter buffer indicating the number of lines at the trailing end of the document is set to -1.
(Step 111). Thus, the transmission of the read image information of the document is started (TD in FIGS. 3 and 4). The line counter and counter buffer are stored in the memory RAM in the CPU 26.
Is set to

Now, since the original 53 is fed in the direction A shown in FIG. 1, the reading position 51 on the original by the CCD 4 on the original moves in the direction of arrow S shown in FIG. 3 or FIG. And
A sub-scan operation is performed. In this process, image reading and image information transmission are performed line by line, and 1 is stored in the line counter.
The addition is repeated (steps 112, 113, 11).
Four). The subsequent operation will be described for each mode described above.

(1) Sheet mode: Every time one line is read, a line counter inspection (step 118) and a paper feed sensor 11 inspection (step 119) are performed. If the line counter becomes equal to the given maximum document length before the trailing edge is detected by the paper feed sensor 11, the light source 1 is turned off (step 134), and the paper is fed until the trailing edge of the document is detected by the paper ejection sensor 12. (Steps 135 and 136). After the detection of the trailing edge of the original, the I / _O line is fed (Step 137), the original 53 is discharged onto the discharge tray 6, and the reading operation is completed.

On the other hand, if the paper feed sensor 11 detects the trailing edge of the original before the line counter counts the maximum original length (FIG. 3,
FIG. 4 TS1) A value obtained by adding ls to the current line count value in the counter buffer is set, and the ls line destination is set as the end line (step 120). Thereafter, reading is performed until the line counter matches the end line set in the counter buffer (steps 121, 122, 123, 124, 126). If they match (TAS in FIGS. 3 and 4), the image transfer is terminated (AC).
K) Send a signal (step 126). At this time, if the original 53 is shorter than the window 52 as shown in FIG. 3 and the window 52 is not terminated (step 127), the reading is continued even after the ACK signal is transmitted until the window 52 is terminated (TAW in FIG. 3). (Steps 121, 122, 123, 124, 127). After the end of the window, turning off the light and discharging the paper are completed, and the reading operation is completed (steps 127, 128, 134, 135, 136 and 137).

(2) Window mode: The window end condition is checked every time one line is read (step 116). Then, when the window is closed (FIGS. 3 and 4
W), an ACK is sent out (steps 131 and 133), the light is turned off, and the reading operation after discharging is ended (steps 134, 135, 136 and 137).

(3) Window second mode: every time one line is read,
An inspection of the window end condition (step 116) and an inspection of the paper feed sensor 11 (step 119) are performed. Feed sensor 1
If the window 53 ends before the trailing edge is detected by the step 1 (TAW in FIG. 4), the ACK signal is transmitted twice (steps 131 and 1).
32,133). The first ACK signal is a dummy original end signal, and the second ACK signal is a window end signal.

If the feed sensor 11 detects the trailing edge of the original before the end of the window (TS1 in FIG. 3), the end of the ls line is set as the end line (steps 119 and 120). Thereafter, reading is performed until the line counter matches the end line (step 124) or until the window ends (step 127) (step 1).
21,122,123). When the manuscript is finished (Fig. 3, TA
S), and sends an original end ACK signal (step 125). Reading is continued until the end of the window. After the end of the window, a window end ACK signal is transmitted (step 133), and thereafter, the operation is turned off and the sheet is discharged (steps 134, 135, 136, and 13).
7).

On the other hand, if the window ends first, the ACK signal is transmitted twice (steps 130 and 133). However, the first time is a dummy document end signal.

As described above, according to the present embodiment, according to the designation of the reading end condition (reading mode) of the external device 31, the end signal (ACK
The output timing of the signal is selected at the end of the original or at the end of the window, and is transmitted. As a result, the range of the original in the window can be appropriately notified to the external device while the image information is being transmitted, so that the external device can determine whether the line being received is necessary or unnecessary during reading. .

Embodiment 2 This embodiment is a basic example of an image reading apparatus in which an external device can select either a document or a designated reading area (window) as an image reading range. A description will be given on the timing chart of FIG. 6 according to the configuration of FIG. 1 and FIG.

After specifying the read designation area (window) 52 and the image information end condition (mode), the external device 31 requests document image information to the image reading device. However, one of the following two types can be selected as the mode.

(1) Sheet mode: the image reading apparatus ends the transmission of image information at the same time as the end of the document, and transmits a normal reading completion signal (ACK signal) (TAS).

(2) Window mode: The image reading device sends an ACK signal at the end of the reading window (TAW) from the reading position 51, regardless of the end of the original, regardless of the end of the document.

The image reading apparatus that has received the document reading request starts transmitting image information in the same order as in the first embodiment (T
D).

 The following operation will be described for each mode.

(1) Sheet mode: Feed sensor every time one line is read
Eleven tests are made. If the paper feed sensor 11 detects the trailing edge of the original (TS1), an ACK signal is transmitted after further reading of the ls line (TAS), the transmission of the image information is completed, the light is turned off, and the paper is discharged.

(2) Window mode: Every time one line is read, the value of the line counter is compared with the window length. When the window ends, an ACK signal is sent out (TAW), sending out of the image information is ended, and the light is turned off and the sheet is discharged.

As described above, according to the present embodiment, it is possible to dynamically change the reading range in accordance with the designation of the external device 31 without redefining or newly establishing a signal line.

(Embodiment 3) FIGS. 7 and 8 are a timing chart (in a window mode, which will be described later) and a flow chart showing the features of the third embodiment of the present invention. A description will be given of three types of signal lines of the interface line with the external device in FIG.

(I) ACK signal (reading range end signal): a signal for notifying the external device 31 that the reading of the read original or the designated reading area (window) selected by the external device 31 has been completed.

(Ii) PE signal (read-out range warning signal): Normally outputs a low level. When a document is selected as the scanning range,
When the window ends earlier, it goes high. Alternatively, when the window is selected as the reading range, the level becomes high when the original is finished first, and the external device 31 is notified of the relationship between the original and the window.

(Iii) PE reset signal: The PE signal is a status signal, and once it goes to the high level, the level is maintained. Therefore, the external device 31 sends it to the image reading device to clear it and set it to the low level. signal.

For example, an error clear signal (or command),
It can also be used as an image reading start request signal (or command).

The external device 31 sets a reading range (reading mode) as
You can select one of the following modes:

(1) Window mode (FIGS. 7 and 8): The image in the designated window 52 is read. When the original 53 is completed while the window 52 is being read, the PE signal becomes high level to notify the external device that the line being sent to the external device 31 is a non-document image.

(2) Sheet mode: an image of the entire original is read.
When the window 52 ends during the reading of the document, the PE signal becomes high level to notify the external device 31 that the line being sent is image information outside the window.

Since the above two modes are completely similar in operation, the window mode will be described.

The image reading apparatus which has received the reading designation area (window), the reading mode designation and the image reading start request from the external device 31 starts image information transmission in the same order as in the first embodiment (steps 201 to 211) (TD). ). However, prior to the transmission of the image information, the PE signal is set at a low level to indicate that it is within the normal range (step 205).

In the window mode, the number of lines to be read is detected (step 215) and the trailing edge of the document is detected by the paper feed sensor 11 (step 216) every time each line is read (steps 212, 213, 214). If the line count matches the window length, an ACK signal is sent (steps 215, 2).
24) After turning off the light and discharging the paper (steps 225, 226, 227, 22
8) Reading ends with the PE signal at low level.

On the other hand, when the trailing edge of the original is detected by the paper feed sensor 11, the number of lines obtained by adding lS lines to the current number of lines is stored in the counter buffer as the original end line (step 217).
Further reading is continued (steps 218, 219, 220). During this time, the end of the document and the end of the window are checked (steps 221 and 223). If the window 52 ends first, after the ACK signal is sent (step 224), the reading ends with the PE signal at low level. Conversely, if the original 53 ends first, the PE signal is set to the high level (step 222), and reading is continued until the end of the window 52 while notifying that the image information in the subsequent windows is not an original image (step 218). ,
219,220). After the window ends, ACK is sent (step
224), turn off the light, and discharge the paper, and end the image reading operation (steps 225, 226, 227, 228).

As described above, according to the present embodiment, by using the PE signal and the PE reset signal, it is possible to appropriately notify the external device 31 of the document range in the window or the window range in the document during transmission of the image information. External device 31
Can determine whether a line being received is necessary during reading.

Fourth Embodiment FIGS. 9 and 10 are a timing chart and a flow chart showing features of a fourth embodiment of the present invention.

Prior to the image reading request, the external device 31 performs the following settings to the image reading device.

(I) Reading designated area (window) (ii) Reading mode designation (iii) Positive allowable range of document length for window ウ イ ン ド ウ l
(+) (FIG. 9) (iv) Negative tolerance △ 1 (−) (FIG. 9) The difference between the window length and the document length is within the range △ 1. If this is the case, it is the upper limit of the difference that allows the number of read lines to be compensated (Dn in FIG. 9) or the excess lines to be discarded (Dp in FIG. 9).

In the present embodiment, in the sheet mode for reading the entire original, the mode is changed to the mode for reading the window only when the original 55 is slightly shorter or slightly longer than the designated window.

The operation will be described below with reference to the flowchart of FIG.

After the designation of the read designation area (window) and the read mode from the external device 31 and the designation of the allowable ranges △ l (+) and △ l (-), the image reading apparatus that receives the image reading start request is the same as the image reading apparatus according to the first embodiment. Transmission of image information is started in the same order (steps 301 to 310) (TD).

Thereafter, the apparatus operates in the sheet mode, and every time one line is read (steps 311, 312, 313), the trailing edge of the original is detected by the paper feed sensor 11 (step 315). If the trailing edge of the document is detected, the number of lines obtained by adding ls lines to the current number of lines is set in the line buffer as the number of end lines of the document (step 316). Immediately, the set end line number is compared with the window length (step 317). If the value obtained by dividing the window length from the end line number is equal to or less than the specified allowable range Δl (+) and simultaneously equal to or greater than −Δl (−), the window length is taken as the end line number (step 318). .

Then, the image reading is continued (Steps S319, 320, 32).
1) When the number of read lines coincides with the number of end lines (step 322), an ACK signal is sent (step 323), the light is turned off, the sheet is discharged, and reading is completed (steps 324 and 32).
5,326,327).

As described above, according to the present embodiment, by providing the allowable range of the document length by the external device, if the document length is slightly shorter than the designated window, the document information is supplemented (Dn). On the other hand, if the length is slightly longer, the image information can be deleted (Dp). Therefore, by specifying an approximate window and an allowable range without strictly measuring the document length, it is possible to eliminate a difference in image information amount caused by a slight difference in length between a plurality of documents.

[Effect of the Invention] As described above, according to the present invention, in accordance with a document reading request from an external device, movement of the document and lighting of the light source are started, and reading of the image reading area designated by the external device is completed. Accordingly, the light source is turned off, and the movement of the document is terminated after the document has passed the document reading position, so that the image signal in the image reading area specified by the external device is reliably output to the external device, and the image signal specified by the external device is also specified. Unnecessary lighting of the light source outside the image reading area can be prevented, and the image reading area specified by the external device can be efficiently read.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image reading apparatus embodying the present invention, FIG. 2 is a circuit block diagram of the image reading apparatus, FIG. 3 is a timing chart for a short document in the first embodiment, and FIG. 5, a timing chart for a long document, FIG. 5 is a processing flowchart of the first embodiment, FIG. 6 is a timing chart of the second embodiment, FIG. 7 is a timing chart of the third embodiment, FIG. Fig. 9 is a processing flowchart of the third embodiment, Fig. 9 is a timing chart of the fourth embodiment, Fig. 10 is a processing flowchart of the fourth embodiment, Fig. 11 is an external view of an optical system moving image reading apparatus, FIG. 12 is an external view of the original moving image reading apparatus. Reference numerals 2 and 3 denote a reading optical system 4 a CCD 5 a document table glass 8 a separation paper feed roller 9 a document conveyance roller 11 a paper feed sensor 13 a paper ejection roller 22 a timing signal generation circuit 23 an image processing circuit 25 Face circuit 26 is CPU 31 is external device

Claims (1)

(57) [Claims] A moving means for moving a document set in a sheet feeding section to a discharge section via a document reading position; a light source for exposing the document moving in the document reading position; A reading element that reads an image of a read original line by line, an output unit that outputs an image signal read by the reading element to an external device, a unit that specifies an image reading area from the external device, and an original document that is moved by the moving unit. Control means for controlling the movement of the document and the exposure of the document by the light source. The control means starts the movement of the document by the moving means and the lighting of the light source according to a document reading request from the external device. Turning off the light source in response to the end of reading the image reading area specified by the external device by the specifying unit, and moving the light source after the document passes the document reading position. Image reading apparatus, characterized by terminating the movement of the document by means.