JPH01307364A - Picture reader - Google Patents

Abstract

PURPOSE:To relive the load of a driver by providing a drive means applying switching drive to the outside of the moving path of a changeover switching optical filters corresponding to the read mode. CONSTITUTION:A changeover means 40 has optical filters 41, 42 corresponding to various read modes and drive means 50, 51 drive the changeover means so as to place the optical filters 41, 42 in an optical path from an original to a read means 30. In case of switching the optical filters 41, 42 and reading the original, the drive means 50, 51 switch the optical filters 41, 42 at the outside of the moving path of the read means 30 and the changeover means 40 without incorporating the drive means 50, 51 in the unit 23. Thus, the read unit 23 is made small in size and light in weight, and the load of the drive means for driving the read unit 23 is relieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an image that can read well both originals without gradation such as characters and originals with gradation such as photographs and halftone originals. Regarding a reading device.

[Conventional technology]

Documents read by digital copying machines, facsimile machines, and the like include non-gradation documents such as characters and drawings, and gradation documents such as photographs. When reading a document with gradation, an image signal read by a solid-state image pickup device such as a CCD is dither-processed using a dither matrix to reproduce halftones suspiciously. However, in the case of halftone originals, moiré occurs due to dither processing. This is mainly due to the interference between the spatial frequency of the document and the spatial scanning line frequency when a dither matrix is used as one pixel, which causes regular unevenness. In order to remove this moiré, a spatial low-pass filter such as a birefringence plate is inserted into the optical path between the document and the solid-state image sensor to blur the document image. However, when reading a non-gradation original such as a text original with this spatial low-pass filter inserted in the optical path,
This is undesirable because the resolution decreases and the reproducibility of characters etc. deteriorates. From the above, multiple optical filters such as spatial low-pass filters and flat glass are used, and in the case of gradation originals, spatial low-pass filters are inserted in the optical path.
On the other hand, in the case of non-gradation originals, an image reading device has been devised in which a flat glass plate having an optical path length equivalent to a spatial low-pass filter is inserted into the optical path (Japanese Patent Laid-Open No. 61-208
No. 962).

5 and 6 show this conventional image reading device,
As shown in FIG.
), and a plurality of mirrors 5 and an imaging lens 6 are provided on the optical path 4 that guides the reflected light from the original to the solid-state image sensor 3.

The birefringent plate 7 and the flat glass 8 are held by an insertion means 9, and by the operation of the insertion means 9, the birefringence plate 7 is inserted into the optical path in the case of a gradation original, and the birefringence plate 7 is inserted into the optical path in the case of a non-gradation original. is switched so that the flat glass 8 is inserted into the optical path. As shown in FIG. 6, the insertion means 9 consists of a filter plate into which a birefringent plate 7 and a flat glass 8 are fitted side by side, and this filter plate 9 is connected to the output shaft 10a of the motor IO.
It is connected to an arm 11 attached to. The motor 10 is connected to a CPU (not shown) such as a microcomputer via a signal line 12. The CPU is connected to a setting means (not shown) for setting a reading mode, and controls the motor 10 according to a mode signal set by the setting means.
control the rotation.

As a result, the filter plate 9 slides, and the birefringent plate 7 and the flat glass 8 are switched according to the document as described above.

By the way, as semiconductor manufacturing technology has improved, long (for example, 300 mm long) reading devices having a large number of solid-state image sensors have been developed, and a close-contact image sensor incorporating this reading device, a light source, and a lens system has been proposed. There is. and,
Image reading devices that read a document image while moving this contact type image sensor in the sub-scanning direction of the document are often used. In the case of this image reading device as well, it is necessary to switch the optical filter depending on the gradation or non-gradation of the document, and the filter plate 9 serving as the means for inserting the optical filter and the motor 1o that drives the filter plate 9 are required. Can be assembled integrally. FIG. 7 shows a folding image reading device, in which a light source 2, a light source 2,
An imaging lens 6, a solid-state image sensor 3, a filter plate 9, a motor 11, and the like are provided. In this apparatus, a reading unit 13 reads a document on a document table 1 while moving at a predetermined speed.

[Problem to be solved by the invention]

However, in conventional image reading apparatuses that read while moving in the sub-scanning direction, the filter plate 9 and the motor 10 that operates the filter plate 9 are built into the reading unit 13, which increases the size and weight of the reading unit 13. As a result, the load on the drive device that scans and drives the reading unit 3 increases, causing trouble in operation. Further, a signal line for driving the motor 1O is also required for the scanning length of the reading unit 13, and design constraints such as consideration of the arrangement position of this signal line are imposed.

[Means to solve the problem]

The present invention has been made in view of the above, and provides an image reading device in which the number of members incorporated in the reading unit is minimized to the necessary minimum in order to improve the operability of the reading unit and expand the degree of freedom in design.

The image reading device of the present invention includes a reading means for reading an image of a document while moving, a setting means for setting a reading mode, and one filter among a plurality of optical filters in an optical path from the document to the reading means. and a driving means that drives the switching means to insert an optical filter corresponding to the reading mode into the optical path, and the driving means is provided outside the movement path of the reading means. It is something that

As the reading means, a contact image sensor is used in which a series of elements such as a light source, an imaging lens, and a solid-state image sensor are assembled. This contact image sensor emits light from a light source, receives reflected light from a document with a solid-state imaging device, and the solid-state imaging device performs photoelectric conversion on the received reflected light and outputs it as a video signal. As a result, the original image is read. Such a reading means operates to read the original image while moving in the sub-scanning direction of the original. The switching means has a plurality of optical filters corresponding to the reading mode, and switches the optical filters so that the optical filters are inserted into the optical path through which the light reflected from the document reaches the solid-state image sensor of the reading means. A switching means for inserting an optical filter corresponding to the reading mode into the optical path moves integrally with the reading means (moves in the sub-scanning direction). For this reason, the switching means and the reading means are incorporated into a case such as a reading unit, and by moving this reading unit, reading is performed in a reading mode corresponding to the document image. Here, the reading mode is set in the setting means, and includes a mode for reading gradation originals such as photographs (photo mode), a mode for reading non-gradation originals such as text (non-photo mode), and a mode for reading gradation originals such as photographs (non-photo mode). Depending on the application equipment, a mode can be selected as appropriate, such as a mode in which the image is read as it is, a grayscale mode in which the image is read by changing the density, and a color filter mode in which the image is read by removing specific colors. The switching means has an optical filter corresponding to these various reading modes. For example, for photographic mode it has an optical filter consisting of a birefringent plate, for non-photographic mode it has an optical filter consisting of flat glass, and for grayscale mode it has an optical filter consisting of a transparent glass plate and a colored glass plate. It has an optical filter. The driving means drives the switching means so that each optical filter corresponding to this reading mode is positioned in the optical path from the original to the reading means. This drive 1
The means is provided outside the travel path of the reading means and the switching means. That is, the driving means is provided outside the reading unit, etc. in which the reading means and the switching means are incorporated. By locating the drive means outside the reading unit in this way, the drive means is separate from the reading unit, making it possible to reduce the weight and size of the reading unit, and reducing the load on the drive device that drives the reading unit. It becomes possible. In this case, the driving means needs to drive the switching means so that the optical filters are switched before or immediately after the reading unit is moved. Therefore, the movement start position (home position) of the reading unit is a suitable location for the driving means. The driving means may be of a fixed type or a movable type as long as it performs the switching drive described above outside the movement path of the reading unit.

[Effect]

With the above configuration, when the reading mode is set by the setting means, the driving means drives the switching means. By this driving, an optical filter corresponding to the reading mode is positioned in the optical path from the original to the reading means. In this state, the reading means and the switching means move in the sub-scanning direction to read the original image according to the reading mode.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a plan view of an embodiment of an image reading apparatus according to the present invention, and FIG. 2 is a side view thereof. Original table 21 on which the original is placed
A guide rail 22 is provided below, and the reading unit 23 is provided to move along the guide rail 22 in the six directions of arrows (sub-scanning direction). This reading unit 22 has drive wires 24 connected to both ends in the moving direction.
Drive wire 24 is connected to a drive motor (not shown) via a pulley (not shown). As a result, the reading unit 23 moves in the six directions of the arrow, and reads the original on the original platen 21 while moving in the sub-scanning direction.

The reading unit 23 consists of a casing with an open top, and is provided with a reading means 30 for optically reading a document image and a switching means 40 for switching an optical filter corresponding to the reading mode.

The reading means 30 includes a light source 31 that irradiates light onto the original, an imaging lens 32 that forms an image of the light reflected from the original, and a solid state that receives the light from the imaging lens 32, converts it into a video signal, and outputs it. A contact type image sensor consisting of an image sensor 33 is used. In this case, the solid-state image sensor 33 is disposed in the main scanning direction of the document to read the document image. The switching means 40 includes two optical filters 41 and 42.
A filter unit 43 is fitted along the main scanning direction.
A switching rod 44 is provided for switching the optical filters 41 and 42 by reciprocating the filter unit 43 in the sub-scanning direction (in the six directions of arrows). In this case, the filter unit 43 slides back and forth on the mounting table 25 provided in the reading unit 23, so that one of the optical filters 43 is placed in the optical path from the document to the solid-state image sensor 33 (in this embodiment, the imaging lens 32 and the solid-state image sensor 33)
It is now located in In this case, a slit (not shown) is formed in the mounting table 25 so that it does not block light. Further, as the optical filters 41 and 42, filters corresponding to the document image reading mode are used. Hence, the manuscript of tonality.

When using an optical filter between the original and the non-gradation original, for example, one of the optical filters 41 may be a crystal plate,
A birefringent plate such as a lenticular plate is selected, and
A flat glass having an optical path length equivalent to that of these birefringent plates is selected as the other optical filter 42, and in the case of a gradation original, an optical filter 41 made of a birefringent plate is inserted into the optical path. In the case of a non-gradation original, an optical filter 42 made of flat glass is inserted into the optical path. Next, the switching rod 44 extends in the main scanning direction and is capable of reciprocating in the same direction (in the direction of arrow B), and an "L"-shaped operating rod 46 is formed from the intermediate portion thereof.
．． 46 has two branches.

The bent tip of each working rod 46, 46 passes through a slit 43a formed in the filter unit 43, and is further inserted into an engagement groove (not shown) formed in the mounting table 45. The slit 43a and the engagement groove have the same shape and size, and are both formed to extend diagonally. Furthermore, a switching plate 47 is integrally formed at both ends of the switching rod 44 to which the driving force of driving means 5o and 51, which will be described later, acts.

Further, the reading unit 23 is provided with a support pipe 48, and the switching rod 44 is slidably inserted through the support pipe 48, so that the entire switching means 40 moves integrally with the reading unit 23. There is.

The driving means 50 and 51 are fixed to the side wall 25 of the main body that supports the reading unit 23 so as to move in the sub-scanning direction. The driving means 50.51 slides the switching rod 44 to which the switching plate 47 is attached in the direction B by applying a magnetic attraction force or the like to the switching plate 47, and this sliding causes the action rod 46 to move the filter unit 43. Slide in six directions. By sliding in six directions, the optical filter 41.4 is
2 switching is performed. In this embodiment, the driving means 5
0.51, actuators such as solenoids are used, and these actuators are located at both ends of the switching rod 44. Such drive means 50.51
is driven by a setting means (not shown) that sets the reading mode.
During driving, the optical filter 41 or 42 corresponding to the reading mode set by the setting means is controlled to be inserted into the optical path.

Next, the present invention will be explained in detail.

In the case of gradation originals such as photographs, the operator selects the photographic mode using the setting means and manually selects the photographic mode. In the photo mode, there is an image with gradation in the original to be read, and this is a mode in which the image is read while maintaining the gradation. In this photo mode, a dither method is used to recreate a multi-tone image in order to output an image with gradation, and since gradation is the main image factor, a moiré erasing method is used. It is necessary to read it by passing it through a birefringent plate. When this photo mode is set by manual keystroke, one actuator 51 of the drive means is turned on and the other actuator 50 is turned off. As a result, the switching rod 44
slides so as to be drawn toward the actuator 51, and the filter unit 43 is moved to the left in FIG. 1 by the action rod 46 of the switching rod 44.

This movement inserts an optical filter 41 such as a birefringent plate into the reading optical path. Therefore, when the reading unit 23 moves in the sub-scanning direction in this state, the original image passes through the optical filter 41 and is read, so that moiré does not occur even in gradation originals.

For non-gradation originals such as text originals, the operator selects the non-photo mode and presses the key manually.

The non-photo mode is a mode in which images without gradation, such as line drawings of characters and symbols, are read at high resolution. Therefore, in the non-photo mode, since reproduction of thin lines is an important factor, it is necessary to perform binarization processing using a fixed darkness value without performing dither processing. By setting the non-photo mode, the actuator 50 of the driving means is turned on, and the actuator 51 is turned on.
becomes OFF. As a result, the switching rod 44 slides in the direction of the actuator 50, and the filter unit 43 is moved to the right in FIG. 1 by the action rod 46. This movement inserts the optical filter 42 made of flat glass into the optical path. The optical filter 42 used has an optical path length optically equivalent to that of the birefringent plate 41, and the solid-state image sensor 33 can read image information well formed.

Therefore, in this state, when the reading unit 23 moves in the sub-scanning direction, a non-gradation original can be read with high resolution.

When switching the optical filters 41 and 42 and reading the original, the driving means 50.51 is not incorporated into the unit 23 so that the driving means 50.51 is located outside the movement path of the reading means 30 and the switching means 40. The optical filters 41 and 42 can be switched even if the optical filters 41 and 42 are switched. Therefore, the reading unit 23 can be made small and lightweight, and the load on the driving means for driving the reading unit 23 can be reduced, making scanning smooth and easy.

Further, since the signal line for transmitting signals to the drive means is also shortened, the degree of freedom in design is expanded.

FIG. 3 shows another embodiment of the present invention, in which a filter unit 64 includes three optical filters 61, 62 .
63 are provided. Optical filter 61.62.63
Examples include a birefringent plate, flat glass, and three types of color filters, or three types of color filters of different colors, or a combination of two types of color filters of different colors and one type of color filter with different color density. These optical filters 61, 62, and 63 can be selected freely as appropriate, and switching of these optical filters 61, 62, and 63 is performed by moving the switching means 40 driven by the driving means 50, 51. Furthermore, the working rod 4
6 is inserted into the filter unit 64.
A stopper means 65 is provided in either the groove 4a or the groove (not shown) of the mounting table. The stopper means 65 is composed of two tmO leaf springs in which a convex portion and a concave portion are assembled facing each other, and by moving between the leaf springs, the operating rod 46 inserts an optical filter corresponding to the reading mode into the optical path. As a result, reading is performed through an optical filter corresponding to the set reading mode.

FIG. 4 shows yet another embodiment of the present invention, in which driving means consisting of actuators 50, 51 such as solenoids is provided in the sub-scanning direction (direction B) of the reading unit 23. Filter unit 7 with optical filters 71, 72
o is a magnetic plate 7 in the part facing the actuator 50, 51.
3.74 is provided so that the magnetic attraction force of the actuator 50.51 acts. Further, the filter unit 70 has a long hole-shaped slit 75 formed in the sub-scanning direction, and a pin 76 is inserted into the slit 75 in a manner such that it cannot be removed.

The pin 76 is connected to the base (not shown) of the reading unit 23 or the like. Note that a cushioning material 52 , 53 is provided on the tip surface of the actuator 50 , 51 , and this tip surface portion is provided with an opening (
(not shown) is inserted into the reading unit 23 from within. Moreover, the optical filter 7 in the filter unit 70
1 is a flat glass, and the optical filter 72 is a birefringent plate. Point D is the reading start position (home position) of the reading unit 23, and the reading unit 2 starts from this position.
3 moves in the direction of arrow B, and at this position the flat glass 71 is located in the optical path of the reading means.

In the above configuration, when the reading mode is manually set to the non-photo mode by the key of the setting means, the actuator 50.51
The reading unit 23 moves in the direction of the arrow b' while not operating. Before this movement starts, the optical filter 71 made of flat glass is located in the optical path, so that reading is performed through the flat glass 71, that is, a non-gradation document can be read satisfactorily. - On the other hand, when the photo mode is set, the actuators 50.51 are activated and the magnetic plate 73.
A magnetic attraction force acts on 74. Accordingly, the filter unit 70 is pulled toward the actuators 50 and 51, and the reading unit 23 moves in the direction of arrow b' in this state. That is, the filter unit 7
0, the reading unit 23 moves while remaining stopped at a fixed position. This movement of the reading unit 23 causes the birefringent plate 72 of the filter unit 70 to coincide with the optical path of the reading means.

That is, the birefringent plate 72 is inserted into the optical path. At the beginning of the darning movement, the pin 76 slides in the same direction within the slit 75, but when it reaches the tip of the slit 75, the pin 76 is prevented from moving further, so the filter unit 7o is moved in the direction indicated by the arrow b'. Acts to push in the direction. Due to this acting force, the filter unit 7o is released from the actuators 50 and 51 and moves together with the reading unit 23.

Therefore, reading via the birefringence Fi 72, that is, good reading of a gradation original can be performed. When one reading/taking operation in such a photo mode is completed, the reading unit 23 returns to the Baum position direction (direction b). During this return, first, the actuator 50.
The filter unit 7o comes into contact with the tip end surface of the filter 51 and stops, and then the reading unit 23 moves to the home position (point D) at Pi +h.

That is, the filter unit 70 is pushed back a little with respect to the reading unit 23, and as a result, the flat glass 71 returns to the optical path of the reading means, and becomes ready for the next reading.

〔Effect of the invention〕

As described above in detail, the present invention provides a driving means for driving the switching for the switching means for switching the optical filter corresponding to the reading mode outside the movement path of the switching means, so that the switching means and the reading means The load on the drive device involved in the movement of the motor can be reduced, smooth operation is possible, and signal lines can be shortened, increasing the degree of freedom in design.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the image reading device of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a plan view showing another embodiment, and FIG. 4 is a plan view showing still another embodiment. 5 is a side view of a conventional reading device having means for switching reading modes, FIG. 6 is a perspective view of the main parts in FIG. 5, and FIG. 7 is a conventional reading device that reads while moving. Example side view. Explanation of symbols 1 ------- Original table 2 - -1 ----
---Light source 3-----One solid-state image sensor 4--
−−−−−Optical path 5−・・−・−Mirror 6−・
−・−Imaging lens 7−−−−−−・−・−Birefringent plate
8---11--Flat glass 9--Insertion means lO---1--Motor 11--
・−Arm 12・−・−・−・−Signal line 13−
------・-Reading unit 21--・--・Document stand 22--・--1---Guide rail 23--・--・--Reading unit 24--------
Drive wire 25-- Body 30-
・−・−・Reading means 3t−−−−1・−Light source
32-----1--Imaging lens 33---Solid-state imaging device 40---Switching means 41---Optical filter (birefringent plate) 42---1 ------Optical filter (flat glass) 43...--1--Filter unit 44--Switching rod 45--Filter unit i3i stand 46-
−−−−−−−−・・Action rod 47−−−−−−
--- Switching plate 48 --- Support pipe 50.51-m --- Drive means 52.5
3-----Buffer plate 61.62.63----
- Optical filter unit 65 - - - - - - - - - Stopper means (plate spring) 70 - - - - - Filter unit 71
．． 72...-Optical filter 73.74--Magnetic plate 75--1--
----Slit 76-----Pin Patent applicant Fuji Xerox Co., Ltd. Agent Patent attorney Taira 1) Tadao 21 ・ Document table 22 Guide rail 23 -- Reading unit 24 Drive wire 25 --
Main body 30 Reading means 31 Light source 32-! L-elephant lens 33 Solid-state image sensor 40 -- Total switching means 41 Optical filter (birefringence plate) 42 Optical filter (if' Temporary rattling glass 3 --- Filter unit 43 a --- Slit 44 --- = Switching rod 45 Filter unit l-Placement stand 46-
Action port F 47 1.7 replacement plate 48-
Support pipe 50.51 --- Drive means Am Sub-scanning direction B Main scanning direction FIG.
1 - Drive means 52.53 Loose IJI plate 61
．． 62.63 Optical filter 64 Filter unit, Toro 4a Slit 65 Stopper means (plate spring) 70 Filter unit 71.72 Optical filter 73.74 - Magnetic plate 75 Pickpocket, door G Pin D Start reading of a removal unit 23 (,7α '13
Main scanning direction 3rd section 4th section

Claims (1)

[Scope of Claims] A reading device that reads a document image while moving in a sub-manipulation direction of the document; a setting device that sets a reading mode according to the document image; and a device that moves integrally with the movement of the reading device; a switching means that has a plurality of optical filters corresponding to the reading mode, and switches the optical filter so that one of the optical filters is positioned in the optical path from the document to the reading means; and the reading mode set by the setting means. The apparatus further comprises a driving means for driving the switching means to insert an optical filter corresponding to the optical filter into the optical path, and the driving means is provided outside the movement path of the reading means and the switching means. Image reading device.