JPH11338202A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high working efficiency that processing speed is increased while automatically discriminating the type of an original. SOLUTION: This image reader is constituted so that a prescanning action is executed by moving a slider unit for fetching information light 3 in a reverse direction to an original carrying direction from the end part of an original ejecting side and fetching the image information of the original by the unit 3 while the original and the unit 3 are passed each other and a main scanning action is executed by moving the unit 3 forward from the end part of an original supply side with respect to the original placed on a placing glass 2 and fetching the image information light of the original when the original is carried to the glass 2 from a tray 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus applied to, for example, a color digital copying machine or an image scanner.

[0002]

2. Description of the Related Art As shown in FIG. 10, for example, an image reading apparatus employed in a conventional color digital copying machine or the like has a lamp 31 and a reflection plate in a housing 1 having a document placing glass 2 as a document reading position. A slider unit (information light capturing means) 3 for capturing information light, which is composed of a mirror 32, is provided movably in the left-right direction toward the plane of the drawing, and a first unit corresponding to the slider unit 3 is provided. ~
In addition to the third mirrors 41 to 43 and the imaging lens 5, a photoelectric conversion element (information light reading means) such as a solid-state imaging device (CCD) 6 for reading optical information of each color of red, green, and blue is provided. I have. An automatic document feeder (ADF) 10 provided on the housing 1 has a document placement tray 11 as a document supply position and a document discharge position 12, and a plurality of documents set on the tray 11 are provided. ,
The originals are sequentially conveyed one by one onto the original placing glass 2 by the original feed rollers 13, and the originals on the original placing glass 2 are sequentially conveyed to the original discharge position by the original discharge rollers 14.

In this image reading apparatus, when a document is set on a document placing tray 11 and a reading process is started,
After the original has been conveyed onto the placing glass 2, the slider unit 3 disposed at the end of the original feeding roller 13 below the original placing glass 2 moves the original discharging roller 1.
4 side, and during the movement, the lamp 3
Light is emitted from the light source 1 and the reflected light (information light) L is first to first.
CCD via the third mirrors 41 to 43 and the imaging lens 5
6 and converted into a predetermined electrical signal,
For example, it is output to a printer unit or the like.

In such an image reading apparatus of a color digital copying machine, in order to appropriately copy various types of originals such as a color original and a monochrome original, the image processing content is switched according to the type of the original. Generally, it is troublesome for the user to manually switch the document type. In particular, when various documents are sequentially fed by the ADF 10, the switching operation is performed every time a document is fed. Must be performed and the ADF 10 cannot be used effectively.

Therefore, an image reading apparatus of an automatic color selection (ACS) system capable of automatically discriminating the type of a document has been proposed.

In this ACS type image reading apparatus, the image information light is emitted while moving the slider unit 3 from one end to the other end of one original placed on the original placing glass 2. The prescan process is performed to determine the document type based on the information light, and then the slider unit 3 is returned to one end of the document, and then moved again from one end to the other end. In general, the main scanning process of taking in the information light and creating image data based on the information light is executed.

[0007]

However, the above-mentioned conventional image reading apparatus of the ACS system uses a slider unit 3 for a single document placed on the document loading glass 2.
Is performed two reciprocations to execute the pre-scan process and the main scan process, so that the processing speed is reduced and the work efficiency is reduced.

On the other hand, in the prior art, the slider unit 3 is moved from one end of the original to the other end of the original placed on the original placing glass 2 to execute a prescan process and a main scan process. In order to perform the above operation, an image reading apparatus has been proposed in which the slider unit 3 is moved from the other end of the document to one end.

In this apparatus, if the slider unit 3 makes one reciprocation, the pre-scan processing and the main scan processing can be executed, so that the processing efficiency can be improved.

However, in this image reading apparatus, since the pre-scanning process and the main scanning process are performed on the original placed on the original placing glass 2, the original is placed on the loading tray 11 by the ADF 10. The scanning process such as the pre-scanning process is not performed until the slide unit 3
Is in a standby state, so it cannot be said that the slider unit 3 is being effectively used, and there is room for improvement in this respect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus which solves the above-mentioned problems of the prior art and which has a high processing speed and high working efficiency while automatically discriminating the type of a document.

[0012]

To achieve the above object, an image reading apparatus according to the present invention comprises a housing having a document reading position, a document supply position, and a document set at the document supply position. A document feeder that conveys the document to the document reading position of the housing, and is provided movably in a forward direction and a reverse direction with respect to the document conveyance direction by the document feeder in the vicinity of the document reading position in the housing; Information light capturing means for capturing image information light of the document, and information light reading means for reading the image information light captured by the information light capturing means; While conveying from the supply position to the document reading position, the information light capturing means,
A first moving means for moving the document in the opposite direction to capture the image information light of the document by the information light capturing means and to guide the information light to the information light reading means while the document and the information light capturing means pass each other; In the reading process, the information light capturing means is moved in the forward direction with respect to the document arranged at the document reading position, and the image light information of the document is captured by the information light capturing means and the information light is captured. The gist is configured to be able to execute a second reading process which is guided to the reading means.

In the image reading apparatus according to the present invention, when the document set at the document supply position is transported to the reading position, the information light capturing means disposed at the end on the document discharge side is reversed in the document transport direction. The first scanning process is performed as a pre-scan while the information light taking-in means passes the document, while the document conveyed to the document reading position is moved to the document supply end. The second reading process as a main scan is executed while the arranged information light capturing means is moved in the forward direction. For this reason, it is possible to perform two reading processes of a prescan and a main scan only by making the information light take-in unit reciprocate once for one document.

Further, since the pre-scan processing is executed in parallel with the original transport processing, the time required for the pre-scan processing is substantially reduced as compared with the case where the pre-scan processing is performed after the original transport, for example. Can be omitted.

Further, since the pre-scan can be performed before the main scan, the document type can be automatically determined.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description of the embodiment, the same portions as those of the conventional image reading apparatus shown in FIG. 10 are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 1, the image reading apparatus of the present embodiment includes a document feed roller drive control unit 51 for controlling the rotation drive of the document feed roller 12 in the ADF 10,
Based on the information on the original feed amount from the means 51,
Document leading edge position calculating means 52 for calculating the leading edge position of the transported document is provided. Further, a unit drive control means 61 for controlling the drive of the slider unit 3 and a lamp lighting control means 62 for controlling the lighting drive of the lamp 31 of the slider unit 3 are provided, and the unit drive control is performed based on the initial position and the like. An illumination position calculation means 63 for calculating a lamp position (lamp illumination position) of the slider unit 3 based on information on the unit movement amount from the means 61 is provided.

In this image reading apparatus, the document feed roller drive control means 51, the unit drive, and the like are controlled based on output signals from the document leading edge position calculation means 52, the illumination position calculation means 63, and other detection means such as various sensors. The driving of each driving unit is controlled by the control unit 61, the lamp lighting control unit 62, and other various control units, and the reading operation described below is performed.

First, as shown in step S1 of FIG.
When a plurality of originals P are set on the original mounting tray 11 of the DF 10 and a read start command is given, the slider unit 3 moves the original discharge rollers 14 along the original mounting glass 2 from the initial position shown in FIG. 2 and is disposed at the end of the document discharge side as shown in FIG. 2 (step S
2).

Thereafter, the prescan processing shown in step S3 is executed.

That is, as shown in FIG. 3, the first original P is conveyed toward the original placing glass 2 by the original feed roller 13, and at the same time, the slider unit 3
Moves toward the document feed roller 13 in the direction opposite to the document transport direction (step S31 in FIG. 9).

Then, as shown in FIG. 4, when the lamp illumination position of the slider unit 3 and the leading end position of the document P coincide (intersect), the lamp 31 is turned on to take in the image information light on the document P. Start (Step S32, S
33).

Here, as described above, the lamp illumination position is calculated by the illumination position calculation means 63,
Since the document leading edge position is calculated by the document leading edge position calculating means 52, the point in time when the two positions match can be accurately determined.

Further, as shown in step S33, the moving speed of the slider unit 3 and / or the conveying speed of the document P are adjusted at the same time as the taking of the image information light is started. That is, a time T1 from the time when the illumination position coincides with the leading end position of the document (lighting start time) to the time when the conveyance of the document P onto the document placing glass 2 is completed, and the end of reading of the slider unit 3 from the time of lighting start. Position (feed roller 13
The movement speed of the slider unit 3 and the conveyance speed of the document P are adjusted so that the time T2 until the movement to the end position (the side end position) is completed is adjusted, and the conveyance of the document P and the reading movement of the slider unit 3 are adjusted. And end at the same time. However, in the present invention, it is not always necessary to adjust the document conveying speed and the unit moving speed.

The adjustment of the document conveying speed and the unit moving speed can be performed, for example, as follows.
First, the size of the document P to be conveyed is determined in advance based on information from a document size detection sensor or the like provided on the document tray 11 so that the conveyance speed of the document P by the feed roller 13 and the illumination start A correlation is established between the time T1 and the time T1 from the time of completion to the completion of conveyance. Then, for example, the moving speed of the slider unit 3 from the start of lighting to the completion of the movement is set to a certain speed,
From the speed, a time T2 from the start of illumination of the slider unit 3 to the completion of the movement is obtained. On the other hand, the transport speed of the document P by the feed roller 13 is determined and set to the speed so that the unit movement time T2 coincides with the time T1 from the start of illumination to the completion of document transport. Speed adjustment can be performed. Conversely, the conveyance speed of the document P from the start of illumination to the completion of conveyance of the document P is set to a certain speed, and the conveyance time T1 of the document P is obtained from the speed, and the time is determined. It is also possible to adjust the moving speed of the slider unit 3 so that T1 matches the unit moving time T2.

Needless to say, in the present invention, the method of adjusting the speed of the document P and the slider unit 3 is not limited to the above method, but any method may be used. The speed may be adjusted so that the conveyance of the document P and the movement of the unit 3 are completed at the same time.

By adjusting the speeds of the document P and the unit 3 in this way, as shown in FIG. 5, the conveyance of the document P and the reading movement of the slider unit 3 are completed at the same time, and the lamp 31 is turned off.

On the other hand, while the slider unit 3 is passing the original P, the reflected light (information light) L of the original is taken into the slider unit 3 and the information light L is transmitted to the first to third mirrors 41 to 43 and The image is read by the CCD 6 via the image lens 5 and converted into a predetermined electric signal, and the type of the document image is determined based on the electric signal.

Here, a method of determining the type of the document image will be described. For example, when determining whether a document is color or black and white, the number of dots in the color area (the ratio of chromatic color dots) to the total number of pixels in the document is determined based on the electrical signals related to the image, and the ratio is set to a predetermined value. When the value is larger than the threshold value, it is determined that the document is a color document, and when the value is smaller than the threshold value, it is determined that the document is a monochrome document.

As described above, when the type of the document P is determined and the pre-scan is completed (step 34 in FIG. 9), FIG.
As shown in step S4, the main scan process is executed.

In the main scanning process, first, as shown in FIG. 6, the slider unit 3 at the pre-scan end position (the end position on the original supply side) turns on the lamp 31, and the end portion on the original discharge side. Move in the positive direction toward.
During this movement, the reflected light L from the document P is transmitted to the CCD 6 via the first to third mirrors 41 to 43 and the imaging lens 5.
Is read and converted to a predetermined electrical signal to create predetermined image data. For example, in the case of a copying machine,
The image data is output to the printer unit.

Then, as shown in FIG. 7, the slider unit 3 is moved to the position where the main scan is completed (the end position on the original discharge side).
Then, the lamp 3 is turned off, and the main scanning process is completed.

After the pre-scanning and main scanning reading processes are completed for the first document P,
The same reading process as described above is performed on the first document P.

That is, as shown by the imaginary line in FIG. 3, the discharging process by the discharging roller 14 is started for the document P on which the reading process is completed, and as shown by the solid line in FIG.
The conveyance process of the second original P by the feed roller 13 is started. Further, the slider unit 3 at the main scan completion position (end position on the document discharge side) moves in the opposite direction toward the end on the document supply side.

Then, in the same manner as described above, the prescan processing is started from the time when the document P and the slider unit 3 coincide (FIG. 4). The conveyance to the glass 2 and the discharge of the first original P are completed (FIG. 5).

Thereafter, the main scanning process shown in FIGS. 6 and 7 is performed on the second original P in the same manner as described above.

The above-described reading process is sequentially performed on all the originals P placed on the original placing tray 11 (steps S3, S4, S5 in FIG. 8).
Is completed, the operation of this apparatus is completed.

According to the image reading apparatus of this embodiment, when the original P is being conveyed from the original placing tray 11 to the placing glass 2, the slider unit 3 arranged at the end on the original discharge side is moved to the original position. While the slider unit 3 is moved in the direction opposite to the transport direction and performs image reading processing as pre-scan while the slider unit 3 passes the document P, the document P conveyed to the mounting glass 2 While moving the slider unit 3 disposed at the end of
Since the image reading process is performed as a main scan, the slider unit 3 is reciprocated once for one document P, and two scans of the prescan and the main scan are performed.
The reading process can be performed twice. For this reason, the moving amount of the slider unit 3 can be reduced by half as compared with a system in which the slider unit 3 is reciprocated each time the pre-scan and the main scan are performed as in a conventional image reading apparatus, and the processing speed is accordingly reduced. It will be faster and higher working efficiency can be obtained.

Further, in the present embodiment, the movement of the slider unit 3 as the pre-scan is completed at the same time as the conveyance of the document P to the placing glass 2 is completed. Time can be substantially omitted, and higher working efficiency can be obtained.

Further, since the pre-scanning process is performed while the original P is being transported, the time required for the pre-scanning process is substantially omitted as compared with the case where the pre-scanning process is performed after the original is transported. And the working efficiency can be further improved.

Further, in the present embodiment, since the amount of movement of the slider unit 3 is halved, the load due to the movement of the slider unit 3 is reduced, and the durability is improved.

Needless to say, the document type can be automatically determined by the prescan, so that there is no need for the user to manually switch the document type, and the switching operation can be omitted.

The present invention is not limited to the image reading device of a copying machine, but can be applied to other image reading devices such as an image scanner.

[0044]

As described above, according to the image reading apparatus of the present invention, when the document set at the document supply position is conveyed to the reading position, the information light taking-in device arranged at the document discharge side end is used. The means is moved in the direction opposite to the document conveying direction, and while the information light capturing means passes the document, the first reading process as prescan is performed, while the document conveyed to the document reading position is Since the second reading process as the main scan is performed while moving the information light capturing unit in the forward direction, the information light capturing unit is set to one for one document.
By simply reciprocating, the reading process can be performed twice, that is, prescan and main scan. For example, compared with the case where the information light capturing unit is reciprocated twice to perform prescan and main scan, the information light reading is performed. The amount of movement of the means can be halved,
The processing speed is increased, and high working efficiency can be obtained. Further, since the pre-scan process is executed during the document conveyance, the time required for the pre-scan process can be substantially reduced compared to the case where the pre-scan process is performed after the document is conveyed. In addition, the processing speed can be further improved. Further, since the pre-scan can be performed before the main scan, there is an effect that the type of the document can be automatically determined.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an image reading apparatus according to an embodiment of the present invention together with a control system block diagram thereof.

FIG. 2 is a schematic sectional view showing the image reading apparatus of the embodiment in an initial state.

FIG. 3 is a schematic cross-sectional view illustrating an upper portion of the image reading apparatus according to the embodiment in a state immediately before starting a prescan.

FIG. 4 is a schematic cross-sectional view illustrating an upper portion of the image reading apparatus according to the embodiment in a state immediately after a pre-scan is started.

FIG. 5 is a schematic cross-sectional view illustrating an upper portion of the image reading apparatus according to the embodiment in a state immediately after a pre-scan is completed.

FIG. 6 is a schematic cross-sectional view illustrating an upper portion of the image reading apparatus according to the embodiment in a state immediately after a main scan is started.

FIG. 7 is a schematic cross-sectional view illustrating an upper portion of the image reading apparatus according to the embodiment in a state immediately after a main scan is completed.

FIG. 8 is a flowchart for explaining a reading operation when the ADF is used in the image reading apparatus of the embodiment.

FIG. 9 is a flowchart illustrating a subroutine at the time of prescan processing in the image reading apparatus according to the embodiment.

FIG. 10 is a schematic sectional view showing a conventional image reading apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Document mounting glass (document reading position) 3 ... Slider unit for information light capture (information light capture means) 6 ... CCD (information light reading means) 7 ... Document loading glass (document reading position) Reference Signs List 10 ADF (document feeding means) 11 Document placement tray (document supply position) 12 Document discharge position L Information light P Document

Claims (1)

[Claims] 1. A housing having a document reading position, a document feeding means having a document supply position and transporting a document set at the document supply position to a document reading position of the housing, and the document in the housing An information light capturing unit provided near the reading position so as to be movable in a forward direction and a reverse direction with respect to a document conveying direction by the document feeding unit, and for capturing image information light of the document; Information light reading means for reading the image information light taken in by the taking means, while conveying the document from the document supply position to the document reading position by the document feeding means, Moving the document in the opposite direction, and while the document and the information light capturing means are passing each other, the image information light of the document is captured by the information light capturing means and the information light reading is performed. A first reading process adapted to guide the information light to the original placed at the original reading position, and moving the information light capturing unit in the forward direction to convert the image information light of the original into the information light. An image reading apparatus configured to execute a second reading process in which the information is read by the reading means and guided to the information light reading means.