JPH0265458A - image input 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 Field of the Invention The present invention relates to an image input device that converts image information into a digital signal, and more particularly to a highly accurate image input device that performs a scanning operation using a linear motor.

BACKGROUND ART FIGS. 2 and 3 are a front view and a side view of an image input device using a conventional linear motor as a drive source, and FIG. 4 is an external view of the linear motor. A platen glass 4 on which a document 2 is placed is supported by a main body frame 6. Main frame 6
A linear motor 8 is fixed approximately at the center. The linear motor 8 is composed of a stator 12 and a mover lO, and the mover 10 includes an optical carriage 14 which will be explained below.
is mounted to perform reading scans in the direction of arrow 16.

Although the driving principle and detailed explanation of the linear motor 8 are not directly related to the present invention, they will be omitted, but the stator 12 is made of iron-based structural material and has high rigidity, and does not deform even when torsion is applied. Guide surface 2 on the upper surface of this stator 12
A mover 10 having four rollers 18 slides and reciprocates.

The guide surface 20 is machined to ensure sufficient flatness (in this embodiment, the flatness is ±50 μm or less).

The optical carriage I4 includes a light source 15 that irradiates the original 2 with light, a fiber lens array 18 that collects reflected light,
The image sensor 20 converts optical information into electrical signals. The fiber lens array 18 has a shallow depth of focus compared to a through lens, so as mentioned above, the guide surface 20 on the stator 12 has sufficient flatness, the stator 12 is highly rigid, and the linear motor 8 is attached to the main body. When attaching to the frame 6, sufficient mounting accuracy is ensured, thereby keeping the distance between the platen glass 4 and the image sensor 20 constant.

Problems to be Solved by the Invention However, although the above configuration has the advantage of being able to accurately feed the image sensor 20 using the linear motor 8, it also has the disadvantage of being quite expensive. are doing.

In view of the above problems, the present invention provides a linear motor that uses an inexpensive stator material and has high precision, and an image input device using the linear motor.

Means for Solving the Problems In order to solve the above problems, an image input device of the present invention includes a platen glass on which a document is placed, and at least a light source, a lens, and an image sensor that convert image information of the document into electrical signals. a linear motor comprising an optical carriage, a mover on which the optical carriage is mounted, and two guide means for guiding the mover, and a stator configured to be substantially twistable about the longitudinal direction as a rotation axis; A main body frame that holds a platen glass and the linear motor, and an adjustment means that adjusts the attachment position of the linear motor to the main body frame,
The book guide means is set in advance so that the surface on which the mover is guided is set substantially parallel, and when the linear motor is fixed to the main body frame, the book guide means is set so that the surface on which the mover is guided is set substantially parallel, and when the linear motor is fixed to the main body frame, the two The guide means is fixed in parallel and at a predetermined distance, so that the distance between the platen glass and the image sensor in the optical carriage is always constant.

According to the above-described structure, the stator material of the linear motor can be made of inexpensive materials, and the accuracy after assembly can be sufficiently improved.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is an external view of the image input device, and FIG. 5 is an external view of the beam near motor. This linear motor 8 has a stator 1
This is a so-called 3-phase full-wavelength coreless coil driven by a coreless coil (not shown) fixed to the 30 tom-halo. The driving principle of this motor is well known and is not directly related to the present invention, so a description thereof will be omitted. The structure of this linear motor 8 is different from conventional examples in that the stator 12 is made of sheet metal bent in a U-shape, and has a structure that can be deformed by torsion in the direction of arrow 32, and there are guides on both sides. Rails 34,36 are fixed and their upper surfaces 38.
40 on which the roller 18 slides. This top surface 3
In this example, the accuracy of 8.40 guarantees a linearity of ±0.1. possible). The guide rails 34, 36 are fixed to the upper surface 38.4 with the stator upper surface 37 as a reference using a jig (not shown).
0 are fixed in parallel and at a constant distance. At this stage, as will be described later, it is not necessarily necessary to ensure the final required accuracy.

An adjustment method for fixing the linear motor 8 to the main body frame 6 will be described below. 2 at both ends of the linear motor 8
A total of four bent portions 42 are formed, and are fixed to the main body frame 6 with four screws 44. In this case, four eccentric pins 46 are arranged near each of the four screws so that the fixing position to the main body frame 6 can be finely adjusted. With the above configuration, the stator 12 can also be fixed in a slightly twisted state.

Next, a specific adjustment method will be explained. A resolution chart consisting of a black and white pattern (81ine pair/m in the present invention)
chart) at the starting position of the optical carriage 14.
48, 49, and 50, and the image sensor 20 performs reading at three positions (not shown) at the end position, and the point where the contrast of the output signal 54 shown in FIG. Adjust the eccentric pin 46 and fix the four screws 44. , the adjustment order is to first place the optical carriage at the starting position and move it to position 48.49.
．． At 50, the signal 54 is checked and the two screws 44 on one side of the linear motor 8 are fixed, and then at the end position (not shown) the signal is checked and the two screws 44 on the opposite side are fixed. By adjusting in this way, even if the guide rails 34, 36 are slightly deviated from the predetermined parallel state as described above, it can be corrected when they are fixed. It also has the advantage that even if the flatness of the platen glass 4 is not ensured, it can be corrected to some extent.

Effects of the Invention As is clear from the above description, there is provided a mover on which an optical carriage is mounted, a stator that is substantially deformable with respect to torsion, and two substantially parallel rods that are fixed to the stator and guide the mover. A linear motor is configured with a guide means,
By adjusting the distance between the platen glass and the two guide means to be kept constant when fixing it to the main body frame, it is possible to realize a highly accurate mechanism using inexpensive parts. In the embodiment of the present invention, the guide rail is constructed as a separate component from the stator, and these components are adjusted using a jig, but the construction is not necessarily limited to this.

[Brief explanation of the drawing]

FIG. 1 is an external view of an image input device according to an embodiment of the present invention, FIG. 2 is a front view of a conventional image input device, FIG. 3 is a side view of a conventional image input device, and FIG. 5 is an external view of the near motor shown in the figure, FIG. 5 is an external view of the near motor shown in FIG. 1, and FIG. 6 is an output waveform diagram of the image sensor. 4...Platen glass, 6...Body frame, 8...Linear motor, 10...
・Mover, 12... Stator, 14...
・Optical carriage, 15...Light source, 18...
...Fiber lens array, 20...Image sensor, 34, 36...Guide rail, 44
...Eccentric cam. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 2? 4 Saitama 3 Figure

Claims (2)

[Claims] (1) A platen glass on which a document is placed, an optical carriage that has at least a light source, a lens, and an image sensor that converts the image information of the document into an electrical signal, a mover on which this optical carriage is mounted, and a guide 2 on which this mover is guided. a linear motor comprising a stator having a book guide means and configured to be substantially twistable with the longitudinal direction as a rotation axis; a main body frame holding the platen glass and the linear motor; and a main body frame of the linear motor. and adjustment means for adjusting the attachment position of the linear motor to the body frame, and the two guide means are set in advance so that the surfaces on which the mover is guided are substantially parallel, and when the linear motor is fixed to the main body frame, , the adjusting means fixes the two guide means parallel to the platen glass surface with a predetermined distance maintained, so that the distance between the platen glass and the image sensor of the optical carriage is always constant. An image input device characterized in that the image input device is configured to be constant. (2) The image input device according to claim 1, wherein the adjustment is performed by reading a resolution pattern original on a platen glass with an image sensor so that the output signal level of the image sensor becomes a predetermined value.