JPH0744114U - Fixed original image reading device - Google Patents

Abstract

(57) [Summary] [Object] To provide a simple structure of a reading optical system for improving the quality of a read image against bending and deformation of a document surface glass of a fixed document type image reading apparatus. [Structure] The carriage 4 is elastically supported by a belt 15 for driving in the sub-traveling direction, which is installed on pulleys 14c and 14d, and a vertical component force of the tension of the belt 15 is generated so that the carriage 4 is covered with a document surface glass 5. It was pushed up in the direction of and was elastically pressed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a fixed original image reading apparatus, in particular, an improvement in which a part of the original reading optical system is displaced according to the deformation of the original placing portion such as the original glass to improve the quality of the read image. It is about structure.

[0002]

[Prior art]

 The fixed original image reading device is suitable for reading originals such as books, but when the weight of a thick book or the pressing force of the operator's hand is applied, the original glass on which the original is set will be deformed. There are cases. In this case, the reflected light from the document is not correctly formed on the photoelectric conversion device element located below the document surface glass, and the quality of the read image may deteriorate. In order to solve this problem, the structure disclosed in Japanese Patent Laid-Open No. 154247/1990 allows a carriage carrying a photoelectric conversion element to move with a document surface glass at a constant distance. Has been proposed. This structure is shown in FIGS. Reference numeral 1 is a rod lens array, 2 is a light source, and 3 is a photoelectric conversion element provided below the rod lens array 1. The elements 1 to 3 are mounted on a carriage 4, and the carriage 4 is supported on a guide shaft 8 arranged parallel to the document surface glass 5 so as to be movable in the sub-scanning line direction. Reference numeral 12 denotes a stepping motor, the rotation of which is reduced by the pulley 14a, the belt 15a, and the pulleys 14b and 14c and transmitted to the belt 15b. The belt 15b is installed between the pulleys 14c and 14d, is fixed to the carriage 4 at the upper side, and has a function of moving it in the sub-scanning direction. Four traveling rollers 21 are attached to the upper part of the carriage 4 so as to contact the lower surface of the document surface glass 5 to travel. The shaft 8 is supported by a pair of brackets 23 fixed to the side plate 6b so as to be vertically movable at both ends. That is, the bracket 23 has an elongated hole 23a extending in the vertical direction, the minor diameter of which is equal to the outer diameter of the shaft 8, and the shaft 8 is positioned by being fitted into the elongated hole 23a. Reference numeral 24 is a spring holder in which a pressing spring 25 is housed. Reference numeral 26 is a bush rod, which is fitted into the spring holder 24 and supported by the pressing spring 25. The notch 26a in the upper portion of the bush rod receives the shaft 8 and presses it upward.

In the above structure, the shaft 8 is supported by the bush rod 26 pressed by the pressing spring 25 and pushed upward. The traveling roller 21 of the carriage 4 supported by the shaft 8 indirectly receives the elastic force of the pressing spring 25 and contacts the original surface glass 5. The bush rods 26, which press both ends of the shaft 8 upward, operate independently of each other, so that all the four traveling rollers 21 contact the original surface glass 5. Therefore, even when the original surface glass 5 is deformed due to the weight of an original such as a thick book or the pressure of the operator's hand, the traveling roller 21 always contacts the original surface glass 5 and travels. Therefore, the posture of the carriage 4 is also displaced according to the deformation. That is, the rod lens array 1 and the photoelectric conversion element 3 mounted on the carriage 4 can always run with a constant distance from the original surface glass 5.

[0004]

[Problems to be solved by the device]

 The conventional structure shown in FIGS. 2 and 3 requires a special bracket 23, a spring holder 24, a spring 25, and a bush rod 26 as a support mechanism of the shaft 8, which increases the cost in terms of the number of parts and the number of assembling steps. Become. In addition, when the parallelism of the left and right guide portions of the carriage 4 is deviated due to the bending of the original surface glass 5 and the eccentricity and wear of the traveling roller 21, the carriage 4 is smoothly moved when the left and right shafts 8 are tilted differently. There is a problem that movement cannot be expected.

The present invention has been proposed in view of the above points, and has a support structure capable of minimizing the number of parts and maintaining the posture of the reading optical system in a predetermined state at all times in accordance with the deformation of the document surface glass. The purpose is to provide.

[0006]

Means for Solving the Problems To achieve the above object, the present invention provides an original document placing portion on which an original document is placed and a rod which receives reflected light from the original document and forms an image on a photoelectric conversion element. A lens array, a carriage that holds this rod lens array and moves in the sub-scanning direction while maintaining parallel to the original document placement section, and a carriage that is attached to this carriage and contacts the lower surface of the original document placement section to make sub-scanning. In a fixed document type image reading apparatus including a traveling roller that travels in the direction and a belt member that drives the carriage in the sub-scanning direction, the belt member applies a tension that elastically presses the carriage toward the document placement portion. It is characterized by adopting a supporting structure that is held and supported.

[0007]

[Action]

 According to this invention, the carriage is supported by the driving belt member itself, and the belt member is provided with a predetermined tension so that the carriage is elastically pressed against the document surface via the traveling roller. With a simple structure, the carriage can be securely brought into close contact with the document surface.

[0008]

【Example】

 FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 2 described above are designated by the same reference numerals, and a duplicated description will be omitted. The driving belt 15 itself installed on the pulleys 14b and 14d elastically supports the carriage 4 independently. At this time, the fixing portion of the carriage 4 is positioned below the position where the belt 15 is originally stretched by a height h. By doing so, a vertical component force with respect to the tension of the belt 15 is generated. Due to this vertical component force, the carriage 4 is pushed up and comes into close contact with the original placement portion, for example, the lower surface of the original surface glass 5, via the roller 21. Therefore, even when the document surface glass 5 is deformed due to the weight of a document such as a thick book or the pressing force of the operator's hand, the traveling roller 21 always contacts the document surface glass 5 and travels. can do. As a result, the rod lens array 1 and the photoelectric conversion element 3 can always run with a constant distance with respect to the document surface glass 5. In this case, since the belt 15 supports the carriage 4 by itself, it needs to have a sufficient strength as compared with the conventional belt. Further, since the tension of the belt 15 is used, the parallelism of the carriage 4 in the sub-scanning direction can be sufficiently maintained even without the guide shaft.

[0009]

[Effect of device]

 As is clear from the above description, according to the present invention, the following effects can be obtained. Compared with conventional products, the number of parts is smaller and a guide shaft is not required, so it is possible to reduce weight, size, and cost. Since the carriage is supported by the belt member itself, there is no hindrance to traveling when the carriage moves. Since the positional relationship between the carriage and the document surface is kept constant, defocusing can be prevented especially in a unit magnification optical system having a shallow depth of focus.

It should be noted that the belt member may support both ends of the carriage, or the one end portion may support a predetermined portion.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an entire fixed original type image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing an entire conventional fixed original type image reading apparatus.

FIG. 3 is a perspective view of a main part showing a support structure for the shaft shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rod lens eye 2 Light source 3 Photoelectric conversion element 4 Carrier 5 Document placing part (document surface glass) 14c, 14d Pulley 15 Belt member 21 Traveling roller

Claims (1)

[Scope of utility model registration request] 1. A document placing section for placing a document, a rod lens array for receiving reflected light from the document and forming an image on a photoelectric conversion element, and the document placing section for holding the rod array. A carriage that moves in the sub-scanning direction while maintaining parallelism, a traveling roller that is attached to the carriage and that travels in the sub-scanning direction by contacting the lower surface of the document placing portion, and a belt that drives the carriage in the sub-scanning direction. A fixed original image reading apparatus including a member, wherein the belt member is supported with a tension that elastically presses the carriage toward the original placing portion. Image reading device.