JPH02104164A - Image reading device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a serial scan type image reading device.

<Prior Art> As an image reading device for reading an image formed on a document, an image reading device configured as shown in FIGS. 7 and 8 has been proposed.

To explain the configuration of the image reading device, the image reading means includes a lamp 2°, a lens 3. It is comprised of a light receiving element 4 for detecting reflected light from a document via a lens 3 and converting it into an electrical signal. A main scanning carriage l carrying this image reading means is continuously moved by a main scanning motor 5 in the direction of arrow Y, which is the main scanning direction, from position A to position B, thereby reading an image of a constant width.

The main scanning carriage 1 and the main scanning motor 5 are mounted on a sub-scanning carriage 6. The sub-scanning carriage 6 is guided in movement in the sub-scanning direction by fitting into two sub-scanning rails 7 arranged along the sub-scanning direction. The sub-scanning carriage 6 is driven by a sub-scanning motor 9 fixed to the main body 8 of the apparatus. The driving force of the sub-scanning motor 9 is applied to the drive shaft 1 by the drive shaft O.
1. A passive shaft 12 is provided opposite the drive shaft 11 . The drive shaft 11 and the passive shaft 12
A pulley 13 such as two toothed pulleys is fixed to each of the pulleys 13, and a sub-scanning pulse 4 is wound around each of the pulleys 13.

The sub-scanning belt 14 is fixed to the sub-scanning carriage 6 on both sides of the carriage 6 by unillustrated retaining members. By equally transmitting the driving force of the sub-scanning motor 9 to both sides of the sub-scanning carriage 6, the carriage 6 can be smoothly transported in the sub-scanning direction.

In the image reading device configured as described above, the main scanning motor 5 is driven to move the main scanning carriage 1 in the direction of arrow Y, and a fixed width is read in that direction.

When the reading in the main scanning direction is completed,
The sub-scanning motor 9 is driven to move the sub-scanning carriage 6 in the direction of arrow X, which is the sub-scanning direction, in accordance with the width of the reading, and then stopped. Then, the main scanning carriage 1 is again moved in the main scanning direction to perform reading of a constant width. In this manner, the document is read by moving the main scanning carriage l alternately in the main scanning direction and the sub-scanning direction and in the direction of arrow X from position a to position b.

<Problem to be solved by the invention> In the above image reading device, 300 to 400 dots/i
In order to obtain a resolution of n, the stopping accuracy of the sub-scanning carriage must be approximately 30 to 50 um.

However, in today's world where high-resolution reading is required, the stopping accuracy is required to have an increasingly high value.

In particular, high precision is required for the stopping positions of the main scanning carriage 1 mounted on the sub-scanning carriage 6 at positions A and B, which are both ends of the movement range.

For this reason, the sub-scanning motor 9 in the image reading device
A stepping motor is used as the sub-scanning belt 14, and the driving force of the motor 9 is transmitted to a drive shaft 11 to which two pulleys 13 are fixed. A high-precision timing belt is used as the sub-scanning belt 14. By fixing the sub-scanning heald 14 to both sides of the sub-scanning carriage 6, the driving force of the sub-scanning motor 9 is evenly transmitted to the sub-scanning carriage 6, and the carriage 6 is smoothly moved in the sub-scanning direction. X
is being transported in the direction.

As described above, since the conventional image reading device is driven in the sub-scanning direction by driving on both sides, the number of parts is large, and the processing accuracy and assembly accuracy of these parts must be sufficiently high.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device that can reduce the number of parts and maintain the required stopping accuracy of the sub-scanning carriage.

Means for Solving the Problems> In order to solve the above problems, the image reading device of the present invention continuously moves the image reading means in the main scanning direction and intermittently moves the image reading means in the sub-scanning direction to read the image. In an image reading device for reading, a rail disposed along a sub-scanning direction, a carriage for transporting the image reading means in the sub-scanning direction, and a fitting fixed to the carriage and fitting with the rail. means, a pressing means fixed to the carriage for pressing the rail, a driving means for intermittently transporting the carriage in the sub-scanning direction when reading a document, and applying the driving force of the driving means to the carriage. and a transmission means for transmitting data to one side of the vehicle.

Further, in the image reading device, it is preferable that the rail is formed into a cylindrical shape and the fitting means is configured as a cylindrical bearing.

Effect> According to the above means, since the driving force can be transmitted to one side of the sub-scanning carriage to transport the carriage in the sub-scanning direction,
The number of parts can be reduced.

In addition, by pressing the 1jlJ scanning rail with the pressing means, it is possible to eliminate the influence of the gap that occurs between the rail and the fitting means that fits the rail, and to reduce the inertial force when the sub-scanning carriage stops. can be absorbed.

Therefore, the stopping accuracy of the sub-scanning carriage can be maintained at a high level of accuracy.

<Embodiment> An embodiment of an image reading device to which the above means is applied will be described below with reference to the drawings.

Fig. 1 is a cross-sectional explanatory diagram of the image reading device, Fig. 2 is a perspective explanatory diagram of the sub-scanning carriage, Fig. 3 is an explanatory diagram of the mounting of the pressing member, and Figs. FIG. 6, which is an explanatory diagram of the displacement of the scanning carriage, is an explanatory diagram of another embodiment in which a pressing member is attached. In the drawings, the same parts or parts having the same functions as those described in the conventional example are given the same reference numerals, and the description thereof will be omitted.

In the figure, an original glass 15 for placing an original (not shown) on the upper part of the main body 8 of the apparatus, and a pressure bonding plate 16 for pressing the original placed on the glass 15 are provided. The original placed on the original glass 15 is irradiated by a lamp 2 mounted on the main scanning carriage 1, and the reflected light is detected by a light receiving element 4 such as a COD through a lens 3. The device is configured to convert an image into an electrical signal and read the document.

n; 1 The main scanning carriage 1 is fitted onto a main scanning rail 17 arranged along the Y direction, which is the main scanning direction. Further, a main scanning belt 1 for transmitting the driving force of the main scanning motor 5 is fixed to the main scanning carriage 1 by an engaging member (not shown), and as the main scanning motor 5 rotates, the main scanning belt 1 is fixed to the main scanning carriage 1. It is configured to be able to move back and forth in the main scanning direction. Then, when the main scanning carriage l moves forward, images of the original are continuously read.

The main scanning carriage 1, main scanning motor 5, etc. are mounted on a sub-scanning carriage 6. A cylindrical bearing 19 is fixed to one side of the sub-scanning carriage 6. Also, in the main body 8 of the device, in the sub-scanning direction? A cylindrical sub-scanning rail 2o is provided. The bearing 19 is fitted to the sub-scanning rail 20, so that the sub-scanning carriage 6 can move in the sub-scanning direction by using the sub-scanning rail 20 as a guide.

Further, the sub-scanning carriage 6 is provided with a pressing means 21 for pressing the sub-scanning rail 20. This pressing means 21 includes a pressing spring 21a made of a spring wA or a phosphor bronze plate, and a sliding butt made of a material used for molded bearings such as l'OM attached to the spring 21a. 21b.

A sub-scanning belt 14 for transmitting the driving force of the sub-scanning motor 9 is fixed to the side of the sub-scanning carriage 6 facing the sub-scanning rail 20 (hereinafter referred to as "C drive side") by an engagement member (not shown). ing. Thereby, the sub-scanning carriage 6 is configured to be able to reciprocate in the X direction, which is the sub-scanning direction, as the sub-scanning motor 9 rotates.

A shaft 22 is fixed to the side opposite to the driving side of the sub-scanning carriage 6 (hereinafter referred to as "driven side j").
A support roller 23 is rotatably attached to the. The support rollers 23 are configured to be movable on roller rails 24 provided on the main body 8 of the apparatus.

That is, when the driving force from the sub-scanning motor 9 is transmitted to the sub-scanning carriage 6, the sub-scanning carriage 6 moves in the sub-scanning direction, and with this movement, the support rollers 23 rotate and move on the roller rails 24. It is something.

In the image reading device configured as described above, the light receiving element 4 has the sub-scanning carriage 6 mounted on the main-scanning carriage 1.
The sub-scanning motor 9 is used to transport the
When a certain amount of rotation is performed, this rotation causes the sub-scanning belt 14 to
is transmitted to the sub-scanning carriage 6 via. Then, the sub-scanning carriage 6 moves by a certain amount, that is, in the sub-scanning direction (X direction) corresponding to the reading width, and then stops.

There is a gap of several microns to several tens of microns between the 1J11 normal bearing 19 and the rail 20, and therefore the sub-scanning carriage 6 generates backlash with respect to the sub-scanning rail 20 corresponding to the gap. For this reason, when a so-called one-sided drive method is adopted in which the driving force is transmitted to one side of the sub-scanning carry 7-gear 6,
The backlash on the support roller 23 side is several hundred μm. The backlash generated on the support roller 23 side has a large adverse effect on the stopping accuracy of the sub-scanning carriage 6. still,
The numerical value of the backlash on the support roller 23 side also changes depending on the length in the main scanning direction.

In this embodiment, as shown in FIG. 3, the sub-scanning rail 20 is held and pressed by the bearing 19 and the pressing means 21, so that the bearing 19 and the sub-scanning rail 20 are pressed together.
This eliminates the gap formed between the This prevents play from occurring on the drive side of the sub-scanning carriage 6, and therefore prevents play from occurring on the support roller 23 side due to the gap between the bearing 19 and the sub-scanning rail 20. .

Further, as shown in FIGS. 4 and 5, if the influence of the sliding resistance f on the support roller 23 side cannot be ignored, when the sub-scanning carriage 6 is moved in the sub-scanning direction and stopped, the bearing 19
Due to the gap between the support roller 23 and the sub-scanning rail 20,
There is a possibility that a deviation of ΔX may occur on the side. In this case, it is possible to cope with this by setting the pressing force F of the Calo pressure spring 21a constituting the pressing means 21 so as to sufficiently oppose the sliding resistance.

It also prevents play from occurring due to the gap between the bearing 19 and the sub-scanning rail 20, and
In order to perform the positioning, it is most advantageous to form the sub-scanning rail 20 in a cylindrical shape and to form the bearing 19 in a cylindrical shape.

Further, the pressing means 21 is pressed against the sub-scanning rail 20)
] Constantly pressing with pressure F. Therefore, a sliding friction of 1"ffi occurs between the sliding pad 21b and the sub-scanning rail 20 due to the pressurizing force F. Since this frictional force acts as a brake on the sub-scanning carriage 6, the sub-scanning motor 9 By stopping the rotation, it is possible to absorb the 'IN' force that occurs when the sub-scanning carriage 6 stops.

In the above-mentioned embodiment, the pressing means 21 was configured to press the sub-scanning rail 20 from below as shown in FIG. good. That is, the purpose of the pressing means 21 is to prevent play from occurring due to the gap between the bearing 19 and the sub-scanning rail 20, and as far as this purpose can be achieved, the pressing means 21 can prevent the sub-scanning rail from being generated. The pressing direction of 20 is not limited.

In the above-mentioned embodiment, the support rollers 23 were provided on the driven side of the sub-scanning carriage 6;
It may be a sliding member that slides on the rail, or it may be a cylindrical rail and a bearing member that fits into the rail. In other words, the sliding resistance r on the driven side should be as small as possible. As long as the pressing force F on the sub-scanning rail 20 by the pressing spring 21a on the driving side can counteract the influence of the sliding resistance r on the driven side, The driven member on the driven side may have any configuration.

In the above-mentioned embodiment, the sliding parapet 21b was formed in the shape of a block, but it is also possible to use a rotatable roller-like shape. The material of the sliding pad 21b is preferably one with low sliding resistance, such as P
Materials used for molded bearings such as leaves can be used.

<Effects of the Invention> As explained in detail above, the fitting means provided on the sub-scanning carry nozzle is fitted into the sub-scanning rail disposed along the sub-scanning direction and the sub-scanning rail is pressed. By pressing with the means, it is possible to prevent play from occurring due to the gap between the fitting means and the sub-scanning rail. Furthermore, by pressing the sub-scanning rail with the pressing means, a pressing force is always applied to the sub-scanning rail, and therefore, when the driving force from the driving means stops, it is possible to absorb the inertial force of the sub-scanning carriage. I can do it. Therefore, the accuracy of stopping the sub-scanning carriage can be improved.

As mentioned above, since the stopping accuracy of the sub-scanning carriage can be improved, reading accuracy can be maintained even with a so-called one-sided drive system in which driving force is transmitted to one side of the sub-scanning carriage, and the number of parts can therefore be reduced. It has characteristics such as being able to reduce

[Brief explanation of drawings]

Fig. 1 is a cross-sectional explanatory diagram of the image reading device, Fig. 2 is a perspective explanatory diagram of the sub-scanning carriage, Fig. 3 is an explanatory diagram of the mounting of the pressing member, and Figs. FIG. 6 is an explanatory diagram of the displacement of the scanning carriage, FIG. 6 is an explanatory diagram of another embodiment in which a pressing member is attached, and FIGS. 7 and 8 are explanatory diagrams of a conventional image reading device. 1 is a main scanning carriage, 5 is a main scanning motor, 6 is a sub-scanning carriage, 8 is a device main body, 9 is a sub-scanning motor, 1
3 is a pulley, 14 is a sub-scanning belt, 19 is a bearing, 20
21 is a sub-scanning rail, 21 is a pressing means, 21a is a Calo pressure spring, 21b is a sliding pad, 23 is a support roller, 24 is a roller rail, r is a sliding resistance, and F is a pressing force. Patent applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) In an image reading device that reads an image by continuously transporting an image reading means in the main scanning direction and intermittently transporting it in the sub-scanning direction, a rail disposed along the sub-scanning direction; a carriage for transporting the image reading means in the sub-scanning direction; a fitting means fixed to the carriage and fitting to the rail; a pressing means fixed to the carriage for pressing the rail; An image reading device comprising: a drive means for intermittently transporting the carriage in the sub-scanning direction during reading; and a transmission means for transmitting the driving force of the drive means to one side of the carriage. . (2) The image reading device according to claim (1), wherein the rail is formed in a cylindrical shape and the fitting means is a cylindrical bearing.