JPH01859A - Image reading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention reads a document using, for example, reflected light or transmitted light, and outputs the read image signal to an external device such as a computer. The present invention relates to an image reading device.

(Prior Art) Recently, as the functions of personal computers and the like have improved, image reading devices for inputting various image information into computers have become commonly available.

Some of the image reading apparatuses described above read a document using transmitted light. This transmitted light is used for originals with positive images or negative images drawn on transparent film or OHP paper.

If you try to read a positive image on the transparent film mentioned above using reflected light, the resolution will drop due to the diffusion of the document cover surface (white surface), that is, the light going around, causing fine lines to disappear or blurring. Therefore, reading is performed using transmitted light.

In this case, the first scanner having an illumination lamp that emits transmitted light and the second scanner having a photoelectric converter are provided separately with the document mounting table in between, and are driven separately. . Therefore, there is no compensation that the CCD sensor (photoelectric converter) surface in the second scanner is aligned with the optical axis of the illumination lamp in the first scanner. As a result, when assembling this device, it is necessary to adjust the optical axis by some method, and conventionally the CCD
The device had to be adjusted while observing the sensor output, making it an inefficient device.

Furthermore, because the adjustment was made during assembly, there was a possibility that the optical axis would become misaligned afterwards. For this reason, there is a drawback that it is not possible to always align the optical axes of the first scanner and the second scanner to read the transparent original with high precision.

(Problems to be Solved by the Invention) As mentioned above, the adjustment efficiency is poor, and it is difficult to always align the optical axes of the first scanner and the second scanner to accurately read a transparent original. In order to eliminate the disadvantage of not being able to read transparent originals, we have developed an image reading device that has good adjustment efficiency, can always align the optical axes of the first scanner and the second scanner, and can read transparent originals with high precision. The purpose is to provide.

[Structure of the Invention (Means for Solving Problems)] The image reading device of the present invention reads image information of a document placed on a document tray, and reads the image information of the document from above the document tray. a first scanner having a transmission light source that irradiates light; a first moving means for moving the first scanner; transmitted light from the first scanner that is transmitted through the original; a second scanner having a photoelectric conversion means for receiving light and converting it into an electrical signal; this second scanner is connected to the first scanner;
a second moving means that moves together with the scanner; and a means for aligning the optical axes of the photoelectric conversion means of the first scanner and the second scanner with respect to the sub-scanning direction when reading the original. It is configured.

(Function) This invention provides an optical axis alignment in the sub-scanning direction of a photoelectric conversion means in the second scanner in a first scanner and a second scanner which are provided separately with a document placing table in between. This is done automatically.

(Example) 1; Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figures 2 to 4 show an image reading device of the present invention that reads reflected light originals (normal originals) or transmissive originals (positive, negative film, OHP paper) and connects them to external devices such as computers. This figure shows a scanner that outputs the read image signal. That is, 1 is a scanner main body, and an operation panel 61 is provided at the front of the upper surface of this main body 1. A document mounting table (platen glass) 2 made of transparent glass is fixed to the upper surface of the main body 1 .

The main body 1 is provided with a document scanning section 5 that includes a first scanner (transmission unit) 3 and a second scanner (sensor unit) 4, which are provided with a document placement table 2 in between. . The first scanner 3 is provided above the document placing table 2, and by reciprocating along its upper surface in the direction of arrow a in the figure, the first scanner 3 optically scans the document O set on the document placing table 2. The document O is scanned by an illumination lamp (fluorescent lamp) 6 that illuminates the document O, a support member 7a that supports the illumination lamp 6, and a carriage 7 that is connected to the support member 7a through an opening 64. It is configured.

As shown in FIG. 4, the carriage 7 and the support member 7a are guided by a guide rail 8 and a guide shaft 9 so as to be able to reciprocate in the direction of arrow a.

A scanning motor (for example, a pulse motor) 1 as a first moving means capable of forward and reverse rotation is mounted on one end side of the guide shaft 9.
A drive pulley 11 is driven by a motor 0, and a driven pulley 12 is disposed at the other end thereof, and an imming belt 13 is stretched between these pulleys 11 and 12. One point of the timing belt 13 is fixed to the carriage 7 via a fixing member (not shown). This allows the carriage 7 to move linearly by rotating the scanning motor 18 in the forward or reverse direction. The support member 7a is configured to be able to move (without colliding with each other) on the document table 2 via a transparent plate 60, which will be described later.

Further, the second scanner 4 is provided below the document placing table 2, and moves back and forth in the direction of arrow a in the figure along the lower surface of the second scanner 4, thereby scanning the document O set on the document placing table 2. It scans optically, and includes an illumination lamp (fluorescent lamp) 21 that illuminates the original O, a photoelectric converter (photoelectric conversion means) 22 that receives reflected light from the original O or transmitted light from the original O, and an original O It is composed of an optical system (light focusing lens) 23 that guides reflected light or transmitted light from the photoelectric converter 22 to a photoelectric converter 22, and a carriage 24 that supports these.

The photoelectric converter 22 outputs an image of the original O as an electrical signal by photoelectrically converting reflected light or transmitted light from the original O, and is mainly composed of, for example, a CCD type line image sensor.

As shown in FIG. 4, the carriage 24 is guided by a guide rail 25 and a guide shaft 26 so as to be able to reciprocate in the direction of arrow a. A driving pulley 28 driven by a scanning motor (for example, a pulse motor) 27 as a second moving means capable of forward and reverse rotation is disposed at one end of the guide shaft 26, and a driven pulley 29 is disposed at the other end. A timing belt 30 is stretched between these pulleys 28 and 29. One point of the timing belt 30 is fixed to the carriage 24 via a fixing member 31. This allows the carriage 24 to move linearly by rotating the scanning motor 27 in the forward or reverse direction.

Furthermore, a scale 41 is provided on the upper surface of the end portion of the document mounting table 2, which serves as a reference surface on which the document 0 is placed.

Furthermore, a document cover 62 is provided at the top of the main body 1 and can be opened and closed by a hinge (not shown).

A white reflective plate (or reflective paper) 63 is provided as a white cover for reflection on the side of the document mounting table 2 of this document cover 60, and a white reflective plate (or reflective paper) 63 is provided as a white cover for reflection. In some cases, it is used closed to remove wrinkles, warps, etc.

When the document O is for transmission, the document cover 62 is opened as shown in FIG. It is now possible to pass through.

When reading the transparent document 0, a transparent plate 60 is placed as a transparent cover that presses the document 0 on the document table 2. As shown in FIG. The transmitting plate 60 transmits light, that is, the light emitted from the illumination lamp 6, and can remove wrinkles, warping, etc. of the original O by pressing the original O.

When the transparent plate 60 is placed on the original table 2, the transparent plate 60 and the supporting member 7a are prevented from colliding with each other.

The transparent plate 60 is accommodated in a storage section (not shown) in an opening 65 at the bottom of the main body 1.

FIG. 5 schematically shows the overall control system.

That is, the CPU 51 as a control unit that controls the entire system includes an operation panel 52, a standardization circuit 53, a memory 54, a light source control unit 55, 56, a motor drive unit 57, 58, and a
/D converters, respectively.

The operation panel 52 instructs to start reading a document,
It consists of keys for specifying (selecting) whether the document to be read is to be read by reflected light or by transmitted light. The standardization circuit 53 performs standardization (shading correction, photoelectric conversion, etc.) using image data obtained by A/D converting the reflected light or transmitted light from the document and reflection reference data or transmission reference data stored in the memory 54. 22). The memory 54 stores reflection-based data obtained by A/D converting the light reflected by a reference plate for reflection (not shown), and data based on reflection data obtained by A/D-converting the light transmitted by a reference plate for transmission (not shown). It stores data or transmitted light information.

The light source control section 55 controls the j! It is connected to the 1-bright lamp 6 and controls its lighting and light amount.

The light source control section 56 is connected to the illumination lamp 2 and controls its lighting and light amount.

The motor drive section 57 is connected to the scanning motor 10 and drives it. The motor drive section 58 is connected to the scanning motor 27 and drives it. The five A/D converters are connected to the photoelectric converter 22, convert an electric signal from the photoelectric converter 22 into a digital signal, and output the digital signal to the CPU 51.

Next, the operation in the above configuration will be explained. For example, now, using the operation panel 52, the operator selects whether the original O is for reflection or transmission, places the original O on the original mounting table 2, and presses a reading start key (not shown). In this case, if the original O is for reflection, the original cover 62 is closed and the original O is processed.
If the document is for transmission, leave the document cover 62 open and insert the transparent plate 60 from the storage section (not shown) into the document placement table 2.
The document O is placed on top of the document O and processed.

Then, if the reflection mode is selected, the CPU 51 turns on the illumination lamp 21 and turns on the scanning motor 2.
7, the carriage 24 is moved. Thereby, the light from the illumination lamp 21 is irradiated onto the original O via the original placing table 2. This reflected light from the document ○ is guided to the charging converter 22 via the optical system 23. This photoelectric converter 22 converts the light into electrical signals and sends them to five A/D converters. Five A/D converters convert this analog signal into a digital signal.

The signal from the original O from the A/D converter 59 is standardized by the standardization circuit 53 using the reflection reference data stored in the memory 54, and is output as read data to an external device (not shown). Ru.

Further, when the transparent mode is selected, the CPU 51
The illumination lamp 6 is turned on and the illumination lamp 21 is turned off. At this time, both the first scanner 3 and the second scanner 4 are set to the home position H. First, the CPU
51 drives the scanning motor 10 by P steps, thereby moving the carriage 7 (support part 7a) and moving the first scanner 3 from the home position H to the reading origin Q. Thereafter, the first scanner 3 maintains this state.

Next, the CPU 51 moves the carriage 24 by driving the scanning motor 27 by (P-α) steps,
The second scanner 4 is moved to a position α steps before the reading origin Q, and then stopped. Thereafter, the output of the photoelectric converter 22, that is, the analog signal, is supplied to the A/D converter 59. Thereby, the five A/D converters convert this analog signal into a digital signal and output it to the CPU 51.

In this state, the CPU 51 switches the scanning motor 27 to 1.
By driving the step, the carriage 24 is moved by one step, and the second scanner 4 is moved by one step (in the sub-scanning direction).
Move toward the reading origin Q side by steps. And C.P.
At this time, U51 reads the digital signal supplied from A/D converter 59, that is, transmitted light information, and stores it in memory 54. This operation is performed from a position α steps before the reading origin Q to a position α steps ahead of the reading origin Q one step at a time. Then, the CPU 51 detects the maximum transmitted light information, that is, the brightest information, from among the transmitted light information stored in the memory 54, and determines the number of steps (the number of steps from the home position) corresponding to that information. Thereby, the CPU 51 moves the carriage 24, that is, the second scanner 4, by driving the scanning motor 27 by the number of steps minus the current number of steps, and then stops. This allows the second
The scanner 4 is set at a position corresponding to the optical axis of the first scanner 3. In other words, the optical axis of the illumination lamp 6 and the photoelectric converter 2
It is set at a position where the optical axis of No. 2 coincides with the optical axis of No. 2.

For example, if the (P-α)th step is the maximum transmission information, the CPU 51 controls the scanning motor 27 for the number of steps (−2α) obtained by subtracting the current number of steps from the number of steps.
The carriage 24 is moved by driving the second
The scanner 4 is moved to the front of the reading origin Q by α steps and then stopped. Thereby, the optical axis of the illumination lamp 6 and the optical axis of the photoelectric converter 22 are set at a position where they coincide, that is, a position where maximum transmitted light information can be obtained.

Thereafter, the first scanner 3 and the second scanner 4 manage the number of steps differently by the number of -α steps, that is, by setting a step bias of -α from the home position H, Their optical axes are always aligned.

Then, the CPU 51 moves the carriage 7 (support member 7a) and the carriage 24 synchronously by driving the scanning motor taco 0127. As a result, the lighting lamp 6
The light is irradiated onto the original 0 through the transparent plate 60. The light transmitted through this original O is transmitted to the original placing table 2 and the optical system 23.
It is guided to photoelectric conversion HHg 22 via l. This photoelectric conversion: j′:i2, + +:! , converts the light into an electrical signal and sends it to the A/D converter 5().\\. Five A/D converters convert this analog signal into a digital signal.

The original O, 5 and O signals from these five A/D converters are standardized by the standardization circuit 5B using the transmission reference data stored in the memory 54, and are read by an external device (not shown) as read data. output to (no).

As mentioned above, by aligning the optical axes of the first scanner and the second scanner each time a transmission original is read, the first scanner and the second scanner are always aligned and the transmission is transmitted. documents can be read with high accuracy.

In addition, since the above-mentioned optical axis alignment is automatically performed before reading the transparent original, there is no need for many processed parts and viscosity, and the number of adjustment steps can be reduced, leading to improved economic efficiency.

[Effects of the Invention] As detailed above, according to the present invention, the adjustment efficiency is high, and the optical axes of the first scanner and the second scanner can always be aligned, so that the transparent original can be read with high precision. An image reading device that can read images can be provided.

[Brief explanation of drawings]

The drawings are for explaining one embodiment of the present invention, and FIG. 1 is a flowchart for explaining the optical axis alignment operation;
Fig. 2 is a side view schematically showing the main parts of the structure, Fig. 3 is an external view showing the overall structure, Fig. 4 is a perspective view showing the scanner moving mechanism of the document scanning section, and Fig. 5 is the overall structure. FIG. 6 is a block diagram schematically showing a control system, and is only a diagram for explaining optical axis alignment. 2... Operation panel, 3... First scanner, 4...
Second scanner, 5... Original scanning unit, 6.21... Illumination lamp, 10.27... Scanning motor, 22...
'#, Electric transformer converter 1...CPU, 52...Operation panel, 60...Transparent plate, 62...Document cover. Applicant's representative Patent attorney Takeshi Suzue, 1') Figure 3 Figure 4

Claims (2)

[Claims] (1) In an image reading device that reads image information of a document placed on a document platform, a first scanner includes a transmission light source that irradiates light onto the document from above the document platform; A second moving means for moving the first scanner, and a second photoelectric conversion means for receiving transmitted light from the first scanner and converting it into an electrical signal. a scanner; a second moving means for moving the second scanner together with the first scanner; and photoelectric conversion means for the first scanner and the second scanner when reading the document. An image reading device comprising: a means for aligning an optical axis in a sub-scanning direction; (2) The image reading device according to claim 1, wherein the photoelectric conversion means is a line image sensor.