JPH0360568A - Picture reader - Google Patents

Abstract

PURPOSE:To prevent flap of an original and to improve the quality of a reading area by providing a spacer keeping a distance between a read guide plate and a platen plate constant to at least one of faces of the read guide plate and the platen plate opposite to each other. CONSTITUTION:In the case of reading of a still original, a switching member 9 is opened, an original 10A is set on a platen plate 2 and the switching member 9 is closed to press the original 10A onto the platen plate 2 with an original retainer 11 and the original on the platen plate 2 is read. In the case of reading a moving original, the switching member 9 is closed and an automatic paper feeding mechanism 13 feeds the originals 10B on the original platen 12 while being separated one by one and the original 10B passes through a gap between the platen plate 2 and the read guide plate 22 placed above the plate 2. The platen plate 2 and the guide face of the read guide plate 22 have a prescribed distance (d) depending on the spacer 24 to guide the original so as not to be flapped and the original is kept in a desired object field depth.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image reading device used in facsimiles, digital copying machines, image scanners, copying machines, and the like.

2. Description of the Related Art Image reading apparatuses have been known that are capable of performing two types of reading: stationary original reading and moving original reading. As shown in FIGS. 3 and 4, a conventional image reading device of this type includes a main body 1, a platen plate 2 made of transparent glass attached to the main body 1, and a platen plate 2 attached to the main body 1. A line scanner 3 disposed below, a slide shaft 4 that holds the line scanner 3 movably in parallel to the platen plate 2, a pulse motor 6, and a belt for reciprocating the line scanner 3 in the sub-scanning direction. 7. A drive device 5 consisting of a pulley 8 and the like, an opening/closing member 9 provided above the platen plate 2 and capable of opening and closing with respect to the apparatus main body 1, and a document 10 held by the opening/closing member 9.
A document presser 11 for pressing A onto the platen plate 2, a document table 12 formed on the top surface of the opening/closing member 9, and a document table 12.
An automatic paper feeding mechanism 13 that separates the plurality of originals 10B set above one by one and feeds them to the reading point P on the platen plate 2.
(introduction roller 14, feed roller 15, reverse roller unit 6, feed roller 17, etc.), a lower guide plate 18 and an upper guide plate 19 that guide the document 10B so that it passes the reading point P, and discharge the document 10B. Equipped with ejection rollers, etc.

In this apparatus, a document 10A placed on a platen plate 2
When reading the document 10A, the document presser 11 presses the document 10A against the platen plate 2, and in this state, the line scanner 3 travels along the platen plate 2 and reads the document on the platen plate 2.

On the other hand, when reading the document 10B placed on the document table 12, the automatic paper feed mechanism 13 separates the documents on the document table 12 one by one and feeds them, and the document 10B is transferred to the platen plate 12.
The line scanner 3 passing through the reading point P and stopping below the reading point P reads the document.

Here, the portion 19a of the upper guide plate 19 located above the reading point P is arranged with a minute gap from the platen plate 2, and by passing the document through the gap, the portion 19a of the upper guide plate 19 is located above the reading point P. This suppressed the flapping of the manuscript. When a reduction system using a lens and COD is used for the image reading method of the line scanner 3, the depth of field of the line scanner 3 must be defined within a range of ±0.5 fi or less. Therefore, by adjusting the mounting position of the upper guide plate 19 with respect to the opening/closing member 9, the gap is defined to be 1 m or less.

Problem to be Solved by the Invention However, according to this configuration, the portion 1 of the upper guide plate 19
9. It is difficult to set the distance between the platen plate 2 and the platen plate 2 to a desired value, and there is a problem that the quality of the read image deteriorates.

The above problem arises for the following reasons. That is, since the upper guide plate 19 is attached to an opening/closing member that can be opened and closed with respect to the platen plate 2, the distance between the platen plate 2 and the upper guide plate 190 portion 19a may be determined by The dimensional tolerances of various parts such as the rotation mechanism for mounting on the platen plate 2 and the upper guide plate 19 at the reading point P when the opening/closing member 9 is closed as shown in FIG. It is difficult to set the distance to the portion 19a to a desired value. If the distance is too wide, the objects will be out of focus, and if the distance is too narrow, it will be difficult to move the document.

Furthermore, the lower surface of the portion 19a of the upper guide plate 19 is usually painted white, and the white painted surface of the upper guide plate is read before the document reaches the reading point P, and the CCD output value at that time is read. However, if the position of the portion 19a of the upper guide plate 19 fluctuates, the CCD output for white paint will fluctuate.
As a result, the density on the reading side becomes unstable. As a result, the image quality differs from that when the original is placed on the platen plate 2 and read.

Furthermore, in the above-mentioned conventional apparatus, as shown in FIG. 14, when a thick original 10A such as a notebook is placed on the platen plate 2, the opening/closing member 9 is closed in the casing, and reading is performed at the reading point P. In this case, the distance between the portion 19a of the upper guide plate 19 and the platen plate 2 becomes large, and good reading cannot be performed.

The present invention has been made in view of the above-mentioned problems, and it is possible to easily maintain the distance between the platen plate and the reading guide plate arranged above the platen plate to a desired value so as to regulate the traveling position of the original. The object of the present invention is to provide an image reading device capable of reading images.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a reading guide plate which is arranged above the platen plate at a predetermined interval.
Pressing means for holding an opening/closing member that can be opened/closed with respect to the platen plate so that it can move toward and away from the platen plate when the opening/closing member is in the closed position, and for pressing the opening/closing member against the platen plate. Further, a spacer portion is provided on at least one of the opposing surfaces of the reading guide plate and the platen plate to maintain a constant distance between the reading guide plate and the platen plate.

According to the above-described structure, the reading guide plate is pressed against the platen plate through the spacer portion when the opening/closing member is in the closed position, so that the gap between the reading guide plate and the platen plate is always maintained. The spacer section maintains a constant value, making it possible to stabilize the reading image quality.

Embodiment FIG. 1 is a sectional view showing a schematic configuration of an image reading device according to an embodiment of the present invention. Parts that are the same as or similar to those of the conventional example shown in FIGS. 3 and 4 are given the same reference numerals. It shows.

In FIG. 1, 1 is the main body of the apparatus, 2 is a platen plate made of transparent glass attached to the main body 1 of the apparatus, and 3 is a line scanner disposed below the platen plate 2; It is equipped with a light source, a lens system, a mirror-dimensional CCD, etc., and can read the original in a line form by electronic main scanning. Note that a shuttle type scanner may be used instead of the line scanner. 4 is a slide shaft that holds the line scanner 3 movably in parallel to the platen plate 2; 5 is the line scanner 3;
This is a drive device for reciprocating in the sub-scanning direction, and consists of a pulse motor 6, a belt 7, a pulley 8, etc. This drive device 5 can keep the line scanner 3 stationary at a position where it reads the document traveling on the reading point P at the left end of the platen plate 2, and also allows the line scanner 3 to stop at a position to read the document placed on the platen plate 2!
It is configured to be able to travel in the sub-scanning direction in order to read the OA.

Reference numeral 9 denotes an opening/closing member IOA located above the platen plate 2 and provided to be openable/closable with respect to the apparatus main body 1.
, IOB is a document, 11 is a document presser for pressing the document 10A against the platen plate 2, 12 is a document table formed on the upper surface of the opening/closing member 9, and 13 is a plurality of documents 10B set on the document table 12. This is an automatic paper feeding mechanism that separates the paper sheets one by one and feeds them to the reading point P on the platen plate 2.
, a feed roller 15, a reversing roller unit 16, a feed roller 217, and the like. 18.19 is manuscript 10
A lower guide plate and an upper guide plate guide the document 10B toward the reading point P, and a discharge roller discharges the document 10B that has passed the reading point P. These document presser 11, document table 12, automatic paper feeder tank 3, lower guide plate 18, upper guide plate 19, upper ejection roller, etc. are all attached to the opening/closing member 9. 9 is opened and closed with respect to the platen plate 2.

A portion 19a of the upper guide plate 19 located above the reading point P
is arranged at a position far away from the platen plate 2. This is a reading guide plate that regulates the traveling position of the document passing the reading point P on the platen plate 2, and its lower surface is painted white to provide a white reference. This reading guide plate is attached to a portion 19a of the upper guide plate 19 by a compression spring. Therefore, the reading guide plate is attached to the opening/closing member 9 via the compression spring path, the upper guide plate 19, etc., and when the opening/closing member 9 is in the closed position (the state shown in FIG. 1), the platen plate 2 It is located above the platen plate 2, is movable toward and away from the platen plate 2, and is further pressed against the platen plate 2 by a compression spring.

This compression spring is the reading guide plate and platen plate 2.
It constitutes a pressing means for pressing against. Note that the pressing means for pressing the reading guide plate n against the platen plate 2 is not limited to the coil spring shown in the figure, but may also use other types of springs, and may also use the weight of the reading guide plate itself. Good too.

As shown in an enlarged view in FIG. 2, the reading guide plate is provided with spacer portions having a predetermined height d at both ends of the surface facing the platen plate. In this embodiment, the spacer portion 24 includes one protrusion provided on one end and two protrusions provided on the other end. Thus,
The reading guide plate O is pressed against the platen plate 2 by a compression spring, and the guide surface of the reading guide plate O and the platen plate 2 are maintained at a constant distance from each other at a height d on the spacer side. This interval is determined by considering the thickness of the original, the depth of field of the line scanner 3, etc., but is usually 0.5 to 0.
．． It has been confirmed through experiments that the best image quality and original running properties can be obtained at a distance of about 7 m. Therefore, the height of the spacer portion is set to about 0.5 to 0.71111. In this way, by setting the height of the spacer part to a predetermined height, the distance between the platen plate 2 and the guide surface of the reading guide plate B can be set to a predetermined value without being affected by the dimensional accuracy of other parts. can be the value of As mentioned above, in this embodiment, three protrusions are used on the spacer side, but these protrusions can be manufactured at low cost by press working, and the dimensional accuracy of the height can be easily adjusted to ±005 mm. This is a good case as it can fit in the following.

Further, by providing three protrusions (one on one side and two on the opposite side), there is an advantage that the reading guide plate n can stably contact with the platen plate 2. Note that the spacer portion side is not necessarily limited to a projection, and may be constructed by pasting a plate material of a predetermined thickness to both ends of the lower surface of the reading guide plate. Further, a spacer portion may be provided on the upper surface of the platen plate 2.

The operation of the image reading device configured as described above will be described below.

When performing stationary original reading, open the opening/closing member 9,
By setting the original 10A on the platen plate 2 and then closing the opening/closing member 9, the original! The OA is pressed against the platen plate 2 with a document presser 11, and in this state, the line scanner 3 travels along the platen plate 2 and reads the document on the platen plate 2.

Next, when performing document moving type reading, the opening/closing member 9 is kept in a closed state. In this state, the automatic paper feed mechanism 13
separates the original 10B on the original platen 12 and sends it out one by one, the original 10B passes through the gap between the platen plate 2 and the reading guide board above it, and stops below the reading point P. Scanner 3 reads the original. Here, since the aforementioned guide plate and the reading guide plate are pressed onto the platen plate 2 by the compression spring B, the guiding surfaces of the platen plate 2 and the reading guide plate are kept at a constant distance d determined by the spacer part thorns. The original can be guided so that it does not flap, and the original can be kept within a desired depth of field, allowing for good reading. Further, even when the lower surface of the reading guide plate B is painted white and used as a white reference for image signal processing, since the white reference position is stable, good image signal processing is possible. Furthermore,
Even if the opening/closing member 9 is closed in the case 1 in which a document thick enough to be used as a document lOA is placed on the platen plate 2, and the opening/closing member 9, document presser 11, etc. are lifted up, the reading guide Since the platen is attached to the opening/closing member 9 with a degree of freedom, the reading guide plate n is pressed against the platen plate 2, and the distance from the platen plate 2 is always kept constant, ensuring good reading. It will be done.

Note that although the above embodiment shows the case where the present invention is applied to an image reading device that is capable of performing moving original reading and stationary original reading, the present invention is not limited to this, and is applicable only to moving original reading. It is also applicable to an image reading device that performs.

Effects of the Invention As is clear from the above description, the present invention provides a moving document reading device in which a reading guide plate, which should be arranged above a platen plate at a predetermined interval, can be opened and closed with respect to the platen plate. The opening/closing member is provided with pressing means for holding the opening/closing member so as to be movable toward and away from the platen plate when the opening/closing member is in the closed position, and for pressing the opening/closing member against the platen plate; By providing a spacer portion on at least one of the mutually opposing surfaces of the plate and the platen plate to maintain a constant distance between the reading guide plate and the platen plate, when the opening/closing member is in the closed position, the reading guide plate is pressed against the platen plate through the spacer section, and therefore, it is possible to always maintain the distance between the reading guide plate and the platen plate at a constant value determined by the spacer section, thereby preventing the document from flapping. Moreover, it has the effect that the quality of the read image can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an image reading device showing an embodiment of the present invention, FIG. 2 is a schematic perspective view showing the main parts thereof, FIG. 3 is a schematic sectional view of a conventional image reading device, and FIG. 4 FIG. 1 is a schematic perspective view showing a conventional image reading device with an opening/closing member open. l...Device body, 2...Platen plate, 3...Line scanner, 4...Slide shaft, 5...Drive device, 9...Opening/closing member, IOA, IOB...Document, 11... Original holder, 12... Original table, 13...
Automatic paper feeding mechanism, 18...lower guide plate, 19...upper guide plate, loading...ejection roller, 缺...reading guide plate,...compression spring, edge...spacer section.

Claims (1)

[Claims] A transparent platen plate, an opening/closing member that can be opened and closed with respect to the platen plate, and a reading guide plate held by the opening/closing member, which is located above the platen plate when the opening/closing member is in the closed position. A reading guide plate movable toward and away from the platen plate, pressing means for pressing the reading guide plate against the platen plate, and at least one of mutually opposing surfaces of the reading guide plate and the platen plate. a spacer section provided on the platen plate to maintain a constant distance between the reading guide plate and the platen plate; a reading means arranged below the platen plate for reading a document passing between the platen plate and the reading guide plate; An image reading apparatus comprising: a paper feeding means for feeding a document between the platen plate and the reading guide plate; and an ejecting means for ejecting the document that has passed between the platen plate and the reading guide plate.