JPH0217760A - Image reading device - Google Patents

Abstract

PURPOSE:To accurately read image data in an effective read area without using a driving system with high accuracy by deciding the image data in the effective read area based on data of correction pattern in a correction area provided outside the effective read area. CONSTITUTION:The correction area where a prescribed correction pattern is applied on an area outside a prescribed effective read area is provided on an original platen. An image reading means 12 reads the correction area with the effective read area. A correction pattern detection circuit 16 detects the correction pattern. A system control part 17 decides the image data in the effective read area based on a detected correction pattern, and the image data is recorded on an image recording means 14 by a memory control part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image reading device, and more particularly to an image reading device in which a carriage carrying an image reading means moves and scans.

(Prior Art) There are various scanning methods for image reading devices, and some scan by moving a carrier equipped with an image reading means.

This scanning type image reading device has one image reading device in the main scanning direction.
An image reading means equipped with sensor elements for a line is mounted on a carrier and moves in the sub-scanning direction, and an image reading means equipped with sensor elements for multiple pixels in the sub-scanning direction is mounted on a carriage and moves in the sub-scanning direction. Move in the scanning direction to perform main scanning,
There is one that repeats this for one page.

In such a scanning type image reading device, the image reading means needs to accurately read only the effective reading area of the document table. In particular, in an image reading device that scans by moving in the main scanning direction an image reading means equipped with sensor elements for multiple pixels in the sub-scanning direction, the main Misalignment is likely to occur in the scanning direction or sub-scanning direction.

Particularly, in a scanning type image reading device in which an image reading means having a sensor element of a plurality of pixel valves is moved in the main scanning direction in the sub-scanning direction, it is necessary to scan the effective reading area l as shown in FIG. , the image reading means 2 is moved in the main scanning direction (first
It is necessary to move it multiple times in the X direction in FIG. 3 and also to move it multiple times in the sub-scanning direction (Y direction in FIG. 13). Therefore, the image data read by the image reading means is
As shown in FIG.
As shown in the figure, the image may shift in the sub-scanning direction.

Therefore, in order to accurately read only the effective reading area of the document table and prevent misalignment during each scan, the precision of the drive system that drives the carriage has been increased, and in particular, a high-precision step motor has been used as the drive motor. etc., or adopted a special drive system.

(Problem to be Solved by the Invention) However, in such conventional image reading devices, in order to accurately read the effective reading area, high-precision drive motors and drive systems, or special drive systems are used. By adopting a
It becomes expensive, the image reading device itself becomes larger,
It was expensive.

(Object of the Invention) Therefore, the present invention provides a correction area having a predetermined correction pattern outside the effective reading means, reads the effective reading area including the correction area with the image reading means, and reads the image data of the correction pattern. By determining the image data of the effective reading area based on the above, the effective reading area can be read accurately without using an expensive drive motor or high-precision drive system, making the image reading device smaller and cheaper. It is intended to become

(Structure of the Invention) In order to achieve the above object, the present invention provides the following features: In an image reading device that moves in a right angle direction to scan a document placed on a document table and reads an image in a predetermined effective reading area, a predetermined correction pattern is formed on the document table outside the predetermined effective reading area. A corrected area is provided, and the image reading means reads the corrected area as well as the effective read area, and determines the image data of the effective area based on the image data of the correction pattern of the corrected area. be.

and (2) the correction pattern is a correction pattern that changes color at a position a predetermined distance from an end of the effective reading area in the moving direction of the carriage.

Hereinafter, the present invention will be specifically explained based on examples.

FIGS. 1 to 8 are diagrams showing one embodiment of the present invention.

In FIG. 1, the image recording device 11 includes an image reading means 12,
drive circuit 13, image recording means 14, memory control section 15,
Correction pattern detection circuit 16 and system control section 17
etc., and the image recording device 1 has an image reading means 12.
The image read in is recorded on recording paper by the image recording means 14, or outputted to a host device (not shown), such as a personal computer, via an interface (not shown).

The image reading means 12 scans a predetermined number of pixels (Yo) in the sub-scanning direction.
) It has arrayed sensor elements, a light source, etc., and the image reading means 12 is mounted on a carriage (not shown). The sensor element divides the reflected light of the light projected onto the document from the light source into each pixel, photoelectrically converts it, and outputs it as read data to the image reading means 14 and the correction pattern detection circuit 16. The document table on which the document is set is formed of a contact glass 21 shown in FIG. 2, and FIG. 2 is a top view of the contact glass 21 viewed from the document side.

The surface of the contact glass 21 on the document side is an effective reading area 38
% correction area, , L, and idle area Au, A4
The correction area is centered around the eight effective reading areas, and is surrounded by the periphery of the correction area, Lm, and idle areas Au and Aa. That is, the correction area and the correction area are respectively formed at both ends of the contact glass 21 in the main scanning direction (X direction in FIG. 2) and extend in the sub scanning direction (X direction in FIG. 2). . Correction area.

and correction area are each a predetermined width (
As shown in FIG. Correction patterns P are applied at predetermined intervals in the sub-scanning direction at the positions. The interval Y of the correction pattern P in the sub-scanning direction is the length YD of the sensor element of the image reading means 12 in the main scanning direction,
In other words, the width is narrower by a predetermined pixel (N) than the scanning width that is read by moving the image reading means 12 once in the main scanning direction.
Y, =Yll-N)! , is.

Further, the correction pattern P is displayed in black, and when a document is set in the effective reading area S1 and the contact glass 21 is covered with a white document holder (not shown), the correction pattern P is displayed.
, will be displayed in black on a white background. Note that the correction area P, L, may be painted white as the ground color, and the correction pattern P may be displayed in black. Naturally, in this case, the correction pattern P1 is applied with the white background color so that the correction pattern P can be read by the image reading means 12.

This effective reading area S has a length of X in the main scanning direction (effective main scanning length: X8) and a length of Y in the sub-scanning direction (
It has an effective sub-scanning length: Y3).

The image reading means 12 moves in the main scanning direction of the contact glass 21 in accordance with the movement of the carry nozzle to main scan the contact glass 21;
At this time, lines corresponding to the number of sensor elements are simultaneously main scanned.

The scanning range XL of the image reading means 12, that is, the reading range in the main scanning direction is the entire length of the contact glass 21 in the X direction, and is expressed as Xt=Xs+2XI. The image reading device 11 can switch between bidirectional scanning and one-sided scanning, and when the image reading means 12 is bidirectional scanning, the contact glass 2.1 moves as shown by the arrow in FIG.
When main scanning is performed from the left end to the right end, sub-scanning is performed by the width Y of the correction pattern P1, and then main scanning is performed from the right end to the left. This operation is sequentially repeated. During unidirectional scanning, the image reading means 12 first main scans from the left end to the right, and when the main scan reaches the right end of the contact glass 21, the image reading means 12 performs a sub-scan of the width Y of the correction pattern P, and then sub-scans the correction pattern P. ,
Return the contact glass 21 to the left end.

Next, main scanning is similarly performed from the left end to the right end of the contact glass 21, and the same operation is repeated until the lower end of the effective reading area S.

Again, in FIG. 1, the drive circuit 13 is a drive circuit for a drive motor that drives the carriage of the image reading means 12, and operates in the main scanning direction (X direction) and the sub scanning direction (Y direction).
The corresponding drive motor is driven for each of the following.

The correction pattern detection circuit 16 detects the correction pattern P of the correction area , L, from the read data outputted by the image reading means 12, and outputs the result to the system control unit F.

The system control unit 17 executes a sequence as the image reading device 11 according to a program stored in the internal memory, and also executes a process of determining image data of the effective reading area S of the present invention. That is, the system control unit 1
7 outputs a control signal to the drive circuit 13 to control the drive of the carriage, controls the reading of the image reading means 12, and also outputs the correction pattern P in the correction pattern detection circuit 16.
The effective reading area S is selected from among the reading data sent from the image reading means 12 to the image recording means 14 based on the detection result.

The image recording means 14 adopts the data as image data.
record it.

The image recording means 14 is equipped with an image memory of a predetermined capacity, and also has a thermal head, a platen, and a drive system for these, and after storing the read data from the image reading means 12 in the image memory, the memory control section The read data determined based on the control of step 15 is adopted as image data and recorded on recording paper.

The memory control section 15 manages the image memory of the image recording means 14 based on support from the system control section 17, and selects image data.

Next, the operation will be explained based on the flowchart shown in FIG.

Now, assume that a document 22 on which the letter "A" is displayed as shown in FIG. 6 is to be read. The operator sets the original on the contact glass 21, and at this time, the original is set in the effective reading area S1 of the contact glass 21.

The operator places the original on the contact glass 21.
L. When the start button (path shown in the figure) of the image reading device 11 is pressed (step P1), the system control unit 17 detects the pressing of the start button and issues a drive instruction in the X direction to the drive circuit 13, and starts driving in the X direction. The motor is driven to move the carriage in the X direction (main scanning direction), and the image reading means 12 starts reading the image (step P).

At this time, as shown in FIG. 3, the image reading means 12 starts main scanning rightward from the upper left end of the contact glass 21, and the correction pattern detection circuit 16 detects the correction pattern P in the correction area. Check whether it has been detected (step P3).

When the correction pattern detection circuit 16 detects the correction pattern P of the correction area Ria, the system control unit 17 calculates the amount of deviation of the image reading means 12 in the Y direction based on the detection result and instructs the memory control unit 15 to , for the X direction,
Instructs the memory control unit 15 to exclude read data by the length (pixels > X) up to the effective read area S.

That is, during main scanning, the image reading means 12 also reads a part of the idle area Au and a part of the correction area, and outputs the read data as recording data. The data is given to the memory control unit 15 so as to exclude the data of the idle area Au and the data of the correction area from this recorded data and adopt only the read data of the effective reading area S. The memory of the image recording means 14 is controlled based on this, and the image recording means 14 records it as image data (step ps).

When the image reading means 12 moves to the right end of the contact glass 21 and main scanning is completed, it checks whether the reading of one page is completed (step Ph), and if it is not completed, it instructs the drive circuit 13 to drive in the Y direction. The carriage is corrected by outputting the pattern P.

is moved in the sub-scanning direction by an interval Y of
). Next, as shown in FIG. 4, the carriage carrying the image reading means 12 is moved from the right end to the left, and main scanning is performed in the same manner. This operation process is repeated in sequence, and when reading and recording of images for one page is completed (step P?
), the carriage is returned to the home position (upper left corner) and the processing for one page is completed (step P9).

When such main scanning and sub-scanning are performed, the image reading means 12 outputs read data as shown in FIG. That is, the sensor pixels of the image reading means 12 are longer than the interval Y1 of the correction pattern 21, and the correction pattern P is always formed vertically by - times of main scanning.

Outputs read data including . This correction pattern P,
In particular, the correction pattern P8 on the main scanning start side is detected by the correction pattern detection circuit 16, and in the Y direction (sub-scanning direction), only the read data between the dashed lines in FIG. 7, that is, the read data between the correction patterns 720 is detected. is adopted as image data. Also, since the distance X from the correction pattern P7 to the effective reading area S is determined, the correction pattern P,
is detected, and the effective reading area S and the correction area are separated from the edge of the effective reading area Ss side of the correction pattern P.

Alternatively, the read data of the distance to the edge of the correction area Lb is excluded from the image data.

Therefore, as shown in FIG. 8, the image data recorded by the image reading means 14 is image data of only the effective reading area S in both the main scanning direction and the sub-scanning direction, and the correction pattern P in the sub-scanning direction. The pieces are accurately joined at the position of . As a result, the image reading means 12
Even if the precision of the drive motor and drive system of the carriage that moves the carriage is not high, it is possible to accurately read images only within the effective reading area S, making the drive motor and drive system of the carriage smaller and cheaper. can do.

Therefore, the image reading device 11 can be made smaller and less expensive.

Note that in the above embodiment, image data determination processing was performed in both the main scanning direction and the sub-scanning direction.
If the deviation in the sub-scanning direction is small and does not pose a problem,
It is sufficient to perform the above image data determination process only in the main scanning direction. In this case, the correction area and the correction area,
The correction pattern P to be applied is not limited to the one shown in Fig. 2.3, but for example, as shown in Fig. 9.10, the correction pattern P applied to the correction area Lll and correction area Lb is drawn in the sub-scanning direction. It may be a black straight line.

At this time, even if the recorded data output from the image reading means 12 is shifted in the main scanning direction as shown in FIG. Based on the detection result of the correction pattern P, only the recorded data within the effective reading area S can be adopted as image data.

In addition, the correction pattern P does not need to be a line,
As shown in FIG. 12, the effective reading area S.

The contact glass 21 may be divided into regions by painting the sides white (W) and the both ends of the contact glass 21 black (indicated by diagonal lines) (B).

Further, in each of the above embodiments, the application is applied to an image reading device that scans multiple times in the main scanning direction, but the invention is not limited to this. The present invention can also be applied to an image reading device that reads one page of a document. In this case, sensor elements are provided over a width greater than the effective reading area (width including the correction area) in the main scanning direction, read the correction pattern of the correction area, and based on the data of this correction pattern, image data of the effective reading area All you have to do is decide.

(Effects) According to the present invention, the image data of the effective reading area can be determined based on the data of the correction pattern of the correction area provided outside the effective reading area.

As a result, image data in an effective reading area can be read accurately without using an expensive drive motor or a high-precision drive system, and the image reading device can be made smaller and cheaper.

[Brief explanation of the drawing]

1 to 8 are diagrams showing an embodiment of the image reading device of the present invention, FIG. 1 is a circuit block diagram of the image reading device, and FIG. 2 is a top surface of the contact glass of the image reading device. Figure 3 is an enlarged view of the main parts of the contact glass, Figure 4 is an explanatory diagram of the scanning method, Figure 5 is a flowchart showing the image data reading process, and Figure 6 shows the original to be read on the contact glass. FIG. 7 is a schematic diagram of the read data, and FIG. 8 is a schematic diagram of image data adopted from the read data. 9 to 11 are diagrams showing other embodiments of the image reading device of the present invention, FIG. 9 is a top view of the contact glass of the image reading device, and FIG. 10 is a main part of the contact glass. The enlarged view, FIG. 11, is a schematic diagram of the read data. FIG. 12 is an enlarged view of a main part of a contact glass showing a correction pattern of still another embodiment of the image reading device of the present invention. 13 to 15 are diagrams showing a conventional image reading device, FIG. 13 is an explanatory diagram of its scanning method, and FIG. 14 shows a state in which the image data is shifted in the main scanning direction. A schematic diagram, FIG. 15, is a schematic diagram showing a state in which the image data is shifted in the sub-scanning direction. 11... Image processing device, 12... Image reading device, 13... Drive circuit, 14... Image recording means, 15... Memory control unit, 16... Correction pattern detection circuit, 17...
...System control unit, 21...Contact glass, S, ...Valid reading area, L, Lb...Correction area, P, ...Correction pattern. Figure// Figure Figure d Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure

Claims (2)

[Claims] (1) An image reading means having sensor elements for multiple pixels in a predetermined direction is mounted on a carriage, and the carriage moves in a direction perpendicular to the arrangement direction of the sensor elements to read the original set on the original platen. In an image reading device that scans and reads an image in a predetermined effective reading area, a correction area provided with a predetermined correction pattern outside the predetermined effective reading area is provided on the document table, and the image reading means reads the image in the effective reading area. An image reading device characterized in that the correction area is read as well as the reading area, and image data of the effective area is determined based on image data of a correction pattern of the correction area. (2) The image reading device according to claim 1, wherein the correction pattern is a correction pattern that changes color at a position a predetermined distance from an end of the effective reading area in the moving direction of the carriage.