JP3004659B2 - Image reading device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus that conveys a document by a platen roller and presses the platen roller with a line image sensor to read a document image line by line.

2. Description of the Related Art In general, in the case of a stationary facsimile apparatus installed indoors, when a document to be read is placed on a document table attached to the apparatus and a start operation is performed, the document is sequentially conveyed one page at a time into the apparatus. Images are read.

By the way, in recent years, a small facsimile machine which is easy to carry is often used. In such a small facsimile machine, a document of many pages is rarely read, and when a document table is attached, it is inconvenient to carry the document. Therefore, in many cases, the document table is not provided.

FIG. 11 shows a conventional example of an image reading section of such a facsimile apparatus. That is, a document insertion slot 2 is formed in the device frame 1, and a document sensor 3 including a light emitting device 3 a and a light receiving device 3 b is provided inside the device frame 1 in that portion. Below them, a platen roller 5 for transporting the original 4 to be inserted and a line image sensor 6 for reading the image by pressing against the platen roller 5 are provided.

When reading an image with this facsimile machine, the operator inserts the document 4 one page at a time into the document insertion slot 2. When the facsimile apparatus detects that the document 4 has been inserted by the document sensor 3, the facsimile apparatus rotates the platen roller 5 by a predetermined amount to pre-feed the document 4, and the leading end thereof is moved to the platen roller 5 and the line image sensor 6 And temporarily wait in a state sandwiched between them. When the start operation is performed, the line image sensor 6 is rotated while the platen roller 5 is rotated at a constant speed to convey the document 4.
The image is read by.

[Problems to be Solved by the Invention] By the way, when an operator inserts a document as described above, the insertion operation is delayed, or the thickness of the document is different, for example, between art paper and tracing paper. If the front end of the original is wrinkled or broken, the end of the original 4 is not completely sandwiched between the platen roller 5 and the line image sensor 6 after completion of the pre-feed, or the width of the sandwich is In many cases, the document 4 was not fixed or the document 4 was inclined.

For this reason, it was difficult for the operator to perform the operation of pre-feeding the document 4 correctly and reliably.

Conventionally, at the end of pre-feed, the width d of the leading end of the document 4 sandwiched between the platen roller 5 and the line image sensor 6 is as short as 1 to 2 mm. For this reason, when the operator pulls the document 4 after the above operation in order to check whether or not the feed is performed correctly, the pre-feed may come off.

However, as described above, if the starting operation is performed in a state where the document 4 is not pre-feeded correctly,
The image reading was not correctly executed from the top of the document because the conveyance of the document 4 was delayed.

As described above, conventionally, there is a problem that since the operation of inserting the document 4 is difficult, the image reading is not always performed stably and correctly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus that solves the above-described problem and that can easily perform an operation of inserting a document and can always correctly read an image.

[Means for Solving the Problems] For this purpose, the invention according to claim 1 includes a document insertion opening into which a document is inserted, a conveyance roller that rotates the document in a fixed direction and conveys the inserted document, and a conveyance roller thereof. An image reading apparatus having a reading sensor that reads a document image line by line by pressing against a document, sequentially reads image information from the reading sensor while rotating a transport roller in a fixed direction when a document is inserted from a document insertion port. Reading and accumulating means for accumulating in the image memory, stopping means for stopping the operation of the reading and accumulating means when the leading end of the document is conveyed to a fixed position beyond the reading line position of the reading sensor, and accumulating in the image memory. Original image information extracting means for extracting only the image information of the actual original image from the image information, and sequentially extracting the image information from the reading sensor while rotating the transport roller again in a certain direction. Image reading means.

According to a second aspect of the present invention, a document inserted from a document insertion port is pressed and held between a conveyance roller and a reading sensor, and the document is read while being conveyed in the direction of the document discharge port with the forward rotation of the conveyance roller. In a conventional image reading apparatus, a conveying roller coupled to a rotating shaft of the conveying roller via a one-way clutch is stationary during normal rotation, and is rotated during reverse rotation to press the conveying roller against a reading sensor for a predetermined rotation angle. A cam that is released to form a gap between the two; a gap detection unit that detects that a gap is formed between the conveyance roller and the reading sensor during the predetermined rotation angle; Document detection means for detecting a document inserted to a certain position beyond the reading line position of the reading sensor through the gap, and detection from the document detection means for detecting a document inserted to the certain position Document reverse transport means for rotating the transport roller in the reverse direction, pressing the original between the transport roller and the reading sensor by passing the cam through a predetermined rotation angle, and returning the leading end of the original to the image reading line position; ,
After the document reverse transporting operation by the document reverse transporting device is completed, the image reading unit sequentially reads the original image while rotating the transporting roller forward, and after the document reading operation by the image reading unit is completed, the transporting roller is reversely rotated again. A gap forming unit that stops the reverse rotation operation of the transport roller with a detection signal from the gap detection unit to stop the cam at a predetermined rotation angle to form a gap between the transport roller and the reading sensor. It is characterized by having.

According to the first aspect of the present invention, the original is conveyed until it moves to a certain position, so that the original is reliably fed for a certain length regardless of the quality of the original insertion operation. In addition, the image reading operation is started during a period until the document moves to a certain position, and thereafter, only the document image is extracted, so that the image reading can always be performed correctly. Become.

According to the second aspect of the present invention, the operator can insert the original in a state in which a gap is formed between the transport roller and the reading sensor, so that the predetermined thickness is not affected by the thickness of the original and the wrinkles of the leading end. The original can be easily inserted in the direction. In addition, after the document is inserted to a certain position in this way, the reading operation is started by returning the document by a certain distance, so that the image reading can always be performed correctly.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a facsimile apparatus according to a first embodiment of the present invention. In the figure, a scanner 11 reads a document image to extract image information, and a plotter 12 records the image information on a recording sheet. The encoding / decoding section 13 encodes image information to be transmitted and decodes received image information. The image memory 14 stores image information.

The network control device 15 performs predetermined transmission / reception operations by capturing a line, transmitting a selection signal as a destination telephone number, detecting an incoming call, and the like. The modem 16 modulates and demodulates image information and transmits the same, and also transmits various procedure signals in a transmission control procedure. The communication control unit 17 controls the network control device 15 and the modem 16 to execute facsimile communication.

The operation display unit 18 displays the operation state of the device,
The operator performs various operations. The system control unit 19 is a microcomputer system and controls the above-described units to execute a predetermined operation of the facsimile machine.

FIG. 2 is a partial cross-sectional view of the image reading unit of the scanner 11. 7, the same reference numerals as those in FIG. 7 denote the same parts or the same parts, and the difference from FIG. 7 is that the platen roller 5 and the line image sensor 6 are below.
An original sensor 7 composed of a light emitting device 7a and a light receiving device 7b
Is that it is arranged.

In the above-described configuration, when transmitting an image, the operator sets a destination on the operation display unit 18, inserts the leading end of the document 4 into the document insertion slot 2, and performs an operation for starting the transmission process.

As shown in FIG. 3, the facsimile apparatus constantly monitors the insertion of the original 4 by the original sensor 3 (step 101).
N loop). When document 4 is detected (step 10
In 1), rotation of the platen roller 5 is started in the transport direction for pre-feeding the document 4 (process 102).
When the inserted document 4 reaches the platen roller 5, it is conveyed by the platen roller 5.

At this time, the document sensor 7 monitors the presence or absence of the document 4 (N loop in process 103), and when the document 4 is detected (Y in process 103), the platen roller 5 for pre-feeding is detected.
Is stopped (step 104).

Next, the operation of the operator is monitored (N loop of process 105), and when the start operation is performed (Y of process 105),
A call is made to the other party (process 106). When the other party answers, returned by a predetermined distance L ₁ which is set to the original 4 in advance by the reverse rotation of the platen roller 5 (step 107). The distance L ₁ is set to a value shorter than the distance L ₀ between the document detecting position of the read line position and the original sensor 7 of the line image sensor 6. Thus, the leading end of the document 4 always stops at a position advanced by the difference (L ₀ −L ₁ ) between the two distances, for example, 5 mm with respect to the reading line position of the line image sensor 6. become.

Thereafter, while conveying the original 4 by rotating the platen roller 5 in the forward direction, the original image is read by the line image sensor 6 and the read image is transmitted to the other party (step 108).

As described above, in this embodiment, after the document 4 is once conveyed until it is detected by the document sensor 7, the document 4 is returned by a certain distance and image reading is started. Accordingly, regardless of the quality of the insertion operation of the document 4 by the operator, the image reading can be executed in a state where the document 4 is securely sandwiched between the platen roller 5 and the line image sensor 6 by a certain width.
The document can be easily inserted and the image can be read correctly.

 Next, a second embodiment of the present invention will be described.

This embodiment has the same hardware configuration as that of the above-described embodiment, but differs in the processing procedure of the image transmission operation.

That is, when transmitting an image, the operator sets the destination on the operation display unit 18, inserts the leading end of the document 4 into the document insertion slot 2, and starts the transmission process, as in the above-described embodiment. Do.

As shown in FIG. 4, when the facsimile apparatus detects the inserted document 4 with the document sensor 3 (Y in step 201), the facsimile apparatus starts rotation of the platen roller 5 for pre-feeding the document 4 (processing 201). 202). At the same time, the image reading operation of the line image sensor 6 is started, and the obtained image information is sequentially stored in the image memory 14 (process 203). This operation is repeatedly executed until the document sensor 7 detects the document 4 (from N in the process 204 to the process 203).

Now, as shown in FIG. 5 (a), when the document 4 is detected by the original sensor 3 at time t _0, the rotation of the platen roller 5 starts at that time t _0. From this point, it takes some time until the leading end of the document 4 reaches the platen roller 5. During this period, since the image reading unit of the line image sensor 6 is in contact with the platen roller 5,
Unnecessary image information is extracted from the line image sensor 6. Then, the tip portion of the original 4, the reading of the actual document image at time t ₁ that has reached the platen roller 5 is started.

When the document sensor 7 detects the document 4 (step 20).
4 Y), the stopped rotation and image reading of the platen roller 5 at the detection time t ₂ (processing 205).

Thus, the image memory 14, as shown in FIG. 6, the unnecessary image information obtained during the period from time t ₀ to t _1, obtained during the period from time t ₁ to t ₂ The image information of the document 4 is stored.

By the way, the time from time t ₀ to t ₁ changes depending on the manner of inserting the document 4, but the time from time t ₁ to t ₂ is when the document 4 is moved from the reading line position of the line image sensor 6 to the document sensor because the distance L ₀ to 7 is a time to move, always constant.

Facsimile machine, then, among the image information in the image memory 14, leaving only the image information read in a predetermined time from time t ₁ to t _2, to erase other unwanted image information (process 20
6).

Next, the operation of the operator is monitored (N loop of process 207), and when the start operation is performed (Y of process 207),
A call is made to the other party (process 208).

Then, when the other party responds, the image information stored in the image memory 14 is transmitted (step 209). Next, while the document 4 is being conveyed by the platen roller 5, the above-mentioned subsequent images of the document 4 are read by the line image sensor 6 and sequentially transmitted (process 210).

As described above, in the present embodiment, the document 4 is
Is pre-feeded to the position, the image is read simultaneously with the conveyance control, only the image information of the original image is extracted at the end of the pre-feed, and when the start operation is performed, the extracted image information is transmitted. The continuation of the image is read and transmitted. As a result, similarly to the above-described embodiment, the document is reliably pre-fed regardless of the quality of the document insertion operation, so that the document insertion operation is facilitated and the image can be read correctly. .

By the way, there is a facsimile apparatus for setting a linear density arbitrarily from a plurality of values when transmitting images. When such a facsimile apparatus performs the above-described processing, the image is read at the highest linear density during pre-feed, and after the start operation is performed, the read image information is converted into the set linear density. , May be transmitted.

 Next, a third embodiment of the present invention will be described.

FIG. 7A is a partial cross-sectional view of the image reading unit in the present embodiment, and FIG. 7B is a cross-sectional view taken along the line AA. In these figures, a platen roller 302 and a line image sensor 303 are provided in an apparatus frame 301. On both sides in the longitudinal direction (one side is not shown), partition plates 304 fixed to the device frame 301 are formed.

A shaft 302a of the platen roller 302 is supported by a bearing 305 attached to a partition plate 304, and a gear 306 is fixed to a tip of the shaft 302a. The gear 306 is supplied with power from a driving device (not shown).

Support shafts 307 are formed at both ends of the line image sensor 303, and the ends of the support shafts 307 are engaged with long holes formed in the partition plate 304 in the vertical direction.

A cam member 308 is inserted into a shaft 302a of the platen roller 302. A one-way clutch mechanism 309 is provided between the cam member 308 and the shaft 302a, and power is transmitted to the cam member 308 only when the shaft 302a rotates in one direction.

Below the line image sensor 303, a spring 310 for pushing the line image sensor 303 upward and a micro switch 311 for detecting a state where the line image sensor 303 is lowered to a predetermined position are provided.

A document insertion port 312 and a document discharge port 313 are formed in the upper part of the apparatus frame 301. A guide plate 314 that guides the inserted document between the platen roller 302 and the line image sensor 303 is formed on the lower surface of the document insertion port 312. The line image sensor 303 has a guide plate 303a for guiding the document in the direction of the document discharge port 313, and a guide plate 315 for guiding the document to the document discharge port 313 on the lower surface of the document discharge port 313. Is formed.

The guide plate 314 is provided with a document sensor 316 including a light emitter 316a and a light receiver 316b, and the guide plate 315 is provided with a document sensor 317 including a light emitter 317a and a light receiver 317b.

With the above configuration, the standby state of the image reading unit is set to the seventh state.
As shown in FIG. 7B, the support shaft 307 is
Line image sensor 30 locked to the raised part of 08
3 drops, platen roller 302 and line image sensor
The state in which a gap is formed between the substrate and 303 is maintained. At this time, the micro switch 311 is connected to the line image sensor 3
It is pushed by 03 and its contact is on.

When reading an image, the operator manually inserts the document 318 from the document insertion slot 312.

As shown in FIG. 8, the facsimile apparatus constantly monitors the insertion of the document 318 by the document sensor 317 (N loop of the process 401).

Then, as shown in FIG. 9A, the document 318 is inserted up to the position of the document sensor 317, and when the document sensor 317 detects the document 318 (Y in process 401), the platen roller
The 302 is rotated by a predetermined angle in the opposite direction to that during image reading.

When the shaft 302a rotates in this direction, the one-way clutch mechanism 309 transmits power to the cam member 308. As a result, the engagement between the cam member 308 and the support shaft 307 is released, the line image sensor 303 rises and presses against the platen roller 302, and the micro switch 311 is turned off. Also, the rotation of the platen roller 302 thereafter causes the original 318
Is returned to the reading line position of the line image sensor 303 as shown in FIG.
02).

In this state, the facsimile apparatus monitors the operation of the operator (N loop of process 403), and when the start operation is performed (Y of process 403), the facsimile machine calls the other party (process 40).
Four). Then, when the other party answers, FIG. 9 (c)
As shown in (5), the platen roller 302 is rotated in a predetermined direction opposite to the above, and while the document 318 is sub-scanned, the document image is read by the line image sensor 303 and transmitted sequentially (process 405).

FIG. 10 shows the subsequent drive control of the platen roller 302. When the platen roller 302 starts rotating in the forward direction for reading a document image (process 501), the detection state of the document sensor 316 is monitored. Then, if the document 318 is detected (step 502), the monitoring is continued as it is (Y loop of the process 502).

When the document sensor 316 no longer detects the document 318 (N in process 502), the process waits for a predetermined time to elapse (a loop in process 502). The certain time is set in advance to a time required for the rear end of the document 318 to move from the position of the document sensor 316 to the reading line position of the line image sensor 303. Therefore, after the elapse of the predetermined time, the image reading of the one page is completed.

When the predetermined time has elapsed (Y in process 503), while rotating the platen roller 302 in the reverse direction (process 504), it is monitored whether or not the contact of the microswitch 311 is turned on (from process N to process 504).

At this time, the cam member 308 rotates in conjunction with the rotation of the platen roller 302, and the raised portion of the cam member 308 pushes down the support shaft 307 as shown in FIG. 9 (d). As a result, the line image sensor 303 descends and the contact of the micro switch 311 turns on.

When the contact of the micro switch 311 is turned on (Y in process 505), the drive control of the shaft 302a is terminated.

As described above, in the present embodiment, the operator inserts the original in a state where the gap is formed between the platen roller 302 and the line image sensor 303. Instead, the original can be easily inserted in a predetermined direction. Then, as in the first embodiment, after the document 318 is inserted to a certain position, the document 318 is returned by a certain distance, and then the image is read, so that the image can always be read correctly.

In each of the embodiments described above, the case where the facsimile apparatus reads and transmits a document image has been described.
It goes without saying that the present invention can be similarly applied to the case of copying an original image. It goes without saying that the same is true not only for the facsimile apparatus but also for the image reading apparatus alone.

According to the first aspect of the present invention, the original is conveyed until it moves to a certain position, so that the original is reliably fed for a certain length regardless of the quality of the original insertion operation. In addition to facilitating the insertion operation, the image reading operation is started until the original moves to a predetermined position, and thereafter, only the original image is extracted, so that the image reading can always be performed correctly. Become like

According to the second aspect of the present invention, the operator can insert the original in a state in which a gap is formed between the transport roller and the reading sensor, so that the predetermined thickness is not affected by the thickness of the original and the wrinkles of the leading end. An original can be easily and reliably inserted in the direction. In addition, after the document is inserted to a certain position in this way, the reading operation is started by returning the document by a certain distance, so that the image reading can always be performed correctly.

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus according to a first embodiment of the present invention, FIG. 2 is a partial sectional view of an image reading section of a scanner, FIG. 3 is a flowchart of an image reading operation at the time of image transmission, FIG. 4 is a flowchart of an image reading operation in the second embodiment of the present invention, FIG. 5 is a time chart showing an operation during execution of pre-feed in the embodiment, and FIG. 6 is an explanation of accumulated image information in the embodiment. FIG. 7 (a) is a partial sectional view of an image reading unit according to a third embodiment of the present invention, FIG. 7 (b) is a sectional view taken along line AA of FIG.
FIG. 9 is a flowchart of an image reading operation in the embodiment, FIGS. 9A to 9D are explanatory diagrams showing operation states of the image reading unit, FIG. 10 is a flowchart of a platen roller drive control operation, and FIG. FIG. 1 is a partial sectional view showing an example of a conventional image reading unit. 1,301: Device frame, 2,312: Original insertion slot, 3a, 7a,
316a, 317a …… Light emitter, 3b, 7b, 316b, 317b …… Receiver, 3,
7,316,317 …… Document sensor, 4,318 …… Document, 5,302…
Platen roller, 6,303 …… Line image sensor, 11
…… Scanner, 12… Plotter, 18… Operation display section, 19
…… System control unit, 304 …… Partition plate, 305 …… Bearing, 30
7: Support shaft, 308: Cam member, 309: One-way clutch mechanism, 310: Spring, 311: Micro switch, 313: Document discharge port.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/00

Claims (2)

(57) [Claims] An original insertion opening into which an original is inserted, a conveying roller for conveying the inserted original by rotating the original in a predetermined direction,
When an original is inserted from an original insertion slot in an image reading apparatus provided with a reading sensor that reads the original image line by line by pressing against the conveying roller, image information is sequentially output from the reading sensor while rotating the conveying roller in a fixed direction. Reading and storing means for taking out an image and storing the image in an image memory; stopping means for stopping the operation of the reading and storing means when the leading end of the document is conveyed to a fixed position beyond the reading line position of the reading sensor; Document image extracting means for extracting only the image information of the actual document image from the image information stored in the printer, and image reading means for sequentially extracting the image information from the reading sensor while rotating the transport roller again in a fixed direction. An image reading apparatus comprising: 2. An image reading method in which a document inserted from a document insertion port is pressed and held between a conveyance roller and a reading sensor, and the document is read while being conveyed in the direction of the document discharge port with forward rotation of the conveyance roller. In the apparatus, the transport roller coupled to the rotating shaft of the transport roller via a one-way clutch is stationary at the time of normal rotation, and is rotated at the time of reverse rotation to release the pressure contact between the transport roller and the reading sensor for a predetermined rotation angle. A cam that forms a gap between the two, a gap detection unit that detects that a gap is formed between the conveyance roller and the reading sensor during the predetermined rotation angle, and a document that is read from the document insertion port through the gap. A document detecting means for detecting a document inserted to a certain position beyond the reading line position of the sensor, and a detection signal from the document detecting means for detecting the document inserted to the certain position. And reverse the transport roller,
A document reverse transport unit that presses a document between a transport roller and a reading sensor by passing a predetermined rotation angle of the cam to return a leading end of the document to an image reading line position; After the conveyance operation is completed, the image reading means sequentially reads the original image while rotating the conveyance roller forward. After the operation of reading the document by the image reading means is completed, the conveyance roller is again rotated in reverse, and the detection by the gap detection means is performed. An image characterized by comprising gap forming means for stopping the reverse rotation operation of the conveying roller by a signal to stop the cam at a predetermined rotation angle and to form a gap between the conveying roller and the reading sensor. Reader.