JPH0313167A - Color picture reader - Google Patents

Abstract

PURPOSE:To miniaturize a color picture reader by supporting a filter member to a read head by an elastic member, positioning the filter member in front of a line image sensor and oscillating the filter member in a sub scanning direction in correspondence to the thrust ripple of a linear direct current motor. CONSTITUTION:The linear direct current motor is provided in a read head 22 equipped with a line image sensor 21 and a filter member, for which optical filters 31-33 in respective colors slender respectively in a main scanning direction are arranged in the sub scanning direction, is supported to the read head 22 by an elastic member 35 and positioned in front of the line image sensor 21. The filter member is oscillated in the sub scanning direction in correspondence to the thrust ripple of the linear direct current motor. Thus, a color picture can be read separately for each color by one line image sensor and since it is not necessary to provide a device such as a solenoid, etc., separately form a sub scanning mechanism for reciprocatively moving the filter member, the color picture reader can be miniaturized.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a color image reading device.

2. Description of the Related Art In recent years, color image reading devices have been developed as image input devices for digital color copying and the like. There are various types of such color image reading devices, and one of them is a device proposed by the present applicant in Japanese Patent Laid-Open No. 62-76857. This color document reading device, which is a color image reading device, is equipped with a line image sensor in which light-receiving elements such as CCDs are arranged in series in the main scanning direction. A filter member in which optical filters are arranged in parallel in the sub-scanning direction is positioned, and the filter member is moved back and forth in the main-scanning direction using a solenoid to switch the colors to be read, and the screen of the document that is relatively moving in the sub-scanning direction is scanned for each color. It is called reading.

Note that the sub-scanning mechanism in the above-mentioned document reading device is one that moves the document in a sub-scanning direction relative to an image sensor fixed to the device, or one that holds the document with a contact glass or the like and uses a reading head equipped with an image sensor as a sub-scanning mechanism. A device that moves the reading head in a scanning manner is considered, and a linear DC motor exists as a means for linearly moving the reading head and the like.

This linear DC motor is a motor in which magnets with alternately different magnetic poles and several types of coils are arranged facing each other, one of which is linearly connected to form a fixed line, and the other is moved relative to each other by changing the magnetic field of the coil.

Therefore, in the linear DC motor 1 shown as an example, the actual structure of this linear DC motor will be explained based on FIG.
N pole S pole 3 where the rail-shaped fixed line 2 is a magnet
. There is. In this linear DC motor 1, the mounting pitch of these Hall elements 9 to 11 is wider than the magnetization pitch of the north and south poles 3 and 4.

In such a configuration, this linear DC motor 1 has the following features:
The excitation of the coils 6 to 8 is controlled by the Hall elements 9 to 11, and the movable element 5 is linearly moved by the magnetic force between the north pole and the south pole 3°4 of the fixed line 2. Here, in such a linear DC motor 1, the thrust force 15 of the mover 5 is obtained by the thrust forces 12 to 14 sequentially generated by the coils 6 to 8, so as illustrated in FIG. Periodic thrust fluctuations called thrust ripple occur.

Problems to be Solved by the Invention The color document reading device described above can read a document for each color by switching the colors to be read by reciprocating the filter member located in front of the line image sensor using a solenoid. However, since a mechanism for reciprocating the filter member is required in addition to a linear motor for relatively moving the line image sensor and the document in the sub-scanning direction, it is difficult to miniaturize the device and save labor.

Means for Solving the Problem A reading head is equipped with a line image sensor in which light-receiving elements are arranged in series in the main scanning direction, and is movably attached to a long fixed line in the sub-scanning direction, and magnets and coils facing each other are provided. A linear DC motor is installed, one of which is attached to the reading head and the other is connected to a fixed line.The linear DC motor is supported by the reading head with an elastic member, is located in front of the line image sensor, and is capable of responding to the thrust ripple of the linear DC motor. A filter member is provided in which optical filters of respective colors vibrating in the sub-scanning direction and elongated in the main-scanning direction are arranged in parallel in the sub-scanning direction.

A linear DC motor is installed in a reading head equipped with a line image sensor, and a filter member in which optical filters of each color elongated in the main scanning direction are arranged in parallel in the sub-scanning direction is supported on the reading head by an elastic member to form a line image sensor. By positioning the filter member in front of the sensor and vibrating it in the sub-scanning direction in response to the thrust ripple of the linear DC motor, a color image can be divided and read for each color with one line image sensor, and the filter member can be read separately. It is not necessary to provide a device such as a solenoid separately from the sub-scanning mechanism for reciprocating movement.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. In the color image reading device 16 of this embodiment, a white fluorescent lamp 18 and a rod lens array 19 are disposed facing each other in the opening at the top of the housing 17.
A reading head 22 is formed by sequentially disposing a filter member 20 and a line image sensor 21, which will be described later, on the optical axis. The reading head 22 is movably held on a fixing line 24 with wheels 23 attached to both sides of the bottom of the housing 17, and faces a contact glass 25 on the top surface of the device from below. Further, in this reading head 22, a linear DC motor 30 is formed by a coil 27 fixed to the bottom surface via a back yoke 26 facing the north and south poles 28° and 29, which are magnets of the fixed line 24. There is. Here, the filter member 2
0 is.

As illustrated in FIG. 4, each RG is elongated in the main scanning direction.
B optical filters 31 to 33 are arranged in parallel with a black part 34 in between, and are positioned in front of the line image sensor 21 with the four corners supported by a base 36 by leaf springs 35 which are elastic members.

In such a configuration, this color image reading device 16
Now, the reading head 22 is moved in a sub-scanning manner by the linear DC motor 30 with respect to the original 37 placed on the contact glass 25 . At this time, due to the thrust ripple of the linear DC motor 30 generated in the moving reading head 22, the leaf spring 3
The filter member 20 supported by 5 is configured to vibrate in the sub-scanning direction. Here, the natural frequency f and amplitude χ of this filter member 20 are the mass m of the filter member 20
From the spring constant k of the leaf spring 35 and the excitation force F of the thrust ripple, it can be determined as follows. In other words, this color image reading device 1
6, for example, the performance of the leaf spring 35 and each optical filter 3.
By setting the widths of 1 to 33 and the characteristics of the linear DC motor 30 to desired values, the line image sensor 21
The reading of the document 37 and the vibration of the filter member 20 are synchronized, and the original 37
The color image is divided into each color by RGB optical filters 31 to 33 and read.

Note that in order to further downsize the device, it is desirable to shorten the leaf spring 35, but this increases the spring constant and reduces the amplitude, which is likely to make the color division operation for reading difficult. Therefore, it is conceivable to match the frequency of the filter member 20 with the period of the thrust ripple of the linear DC motor 30 so that the filter member 20 resonates to ensure a large amplitude. In this case, since the vibration of the filter member 20 does not act on the reading head 22 in addition to the thrust ripple, it is possible to form the color image reading device 16 with high reading accuracy.

Further, in the color image reading device 16 of this embodiment, a black portion 34 is provided between each of the optical filters 31 to 33 of the filter member 20.
is provided, the image light is blocked by the vibrating filter member 20 when the reading color is switched, and color mixture is prevented from occurring in the reading by the line image sensor 21. Furthermore, in this color image reading device 16, a coil 27 is provided on the side of the movable reading head 22 as a linear DC motor 30.
Although the present invention is not limited to a movable coil type linear DC motor with a magnet attached to a movable reading head (not shown), the present invention is not limited to this. ) can also be considered.

Effects of the Invention As described above, the present invention provides a reading head equipped with a line image sensor with a linear DC motor, and a filter member in which optical filters of different colors, each elongated in the main scanning direction, are arranged in parallel in the sub-scanning direction, is attached to the reading head. By supporting the line image sensor with an elastic member and positioning it in front of the line image sensor, and vibrating it in the sub-scanning direction in response to the thrust ripple of the linear DC motor, a color image can be divided into each color with a single line image sensor. To make it possible to read color images, and at the same time, it is not necessary to provide a device such as a solenoid separately from the sub-scanning mechanism to move the filter member back and forth, contributing to miniaturization and labor saving of color image reading devices. This has the advantage that it is possible to produce high-performance digital color copies with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a side view, FIG. 3 is a front view, FIG. 4 is a perspective view of a filter member, and FIG. 5 is a side view showing a linear DC motor. FIG. 6 is an explanatory diagram showing the characteristics of thrust ripple. 16... Color image reading device, 20... Filter member, 21... Line image sensor, 22... Reading head, 24... Fixed line, 27... Coil, 2
8゜29...Magnet, 3o...Linear DC motor, 35...Elastic member J" Figure 1 Atsushi 384 - 1 Atsushi 5

Claims (1)

[Claims] A reading head is provided with a line image sensor in which light-receiving elements are arranged in series in the main scanning direction and is movably attached to a long fixed line in the sub-scanning direction, and one of a magnet and a coil facing each other is attached to the reading head. A linear DC motor is mounted and the other side is connected to the fixed line, and the linear DC motor is supported by an elastic member on the reading head and is located in front of the line image sensor, and performs sub-scanning in response to the thrust force of the linear DC motor. 1. A color image reading device comprising a filter member in which optical filters of each color, each elongated in the main scanning direction and vibrating in the main scanning direction, are arranged in parallel in the sub scanning direction.