JPH04371066A - Image reader - Google Patents

Abstract

PURPOSE:To prevent a driving transmission means from being damaged by the falling impact during transportation by providing a fixing member for transportation on the driving transmission means of an exposure scanning means. CONSTITUTION:Under normal operable condition, gears 10a and 17 are energized by a spring 15 so that they can mesh with each other and the device is operable. The exposure scanning means returns to its home position when it completes one reading operation. At this time, when a switching lever 16 is rotated in the clockwise direction, the gear 17 is rotated clockwise to disengage from the gear 10a, and at the same time, a claw part 14a of a circuit board 14 is energized by the spring 15 so that it can be pushed in a cut-off part 10 of a driving pulley 10, the driving pulley 10 is prevented from rotating and thus fixed to the exposure scanning system.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device for exposing and reading an image on a document onto a reading means such as an image sensor.

0002

2. Description of the Related Art Generally, in an image reading section of a copying machine or an image scanner, a so-called 1:1/1/1/1/1/1/1/1/1/1/1/1/1/1/1 scan is performed by scanning an original placed on an original table glass using a light source and a mirror to expose an image sensor or a photoreceptor. Two optical systems are often used. This 1:1/2 optical system is shown in FIG. FIG. 5(a) is a plan view, and FIG. 5(b) is a side view. As shown in FIG. 5, a fixed original table glass 100
The upper document P is illuminated by the light source LA, and the mirrors M1 and M
2. The image light reflected by M3 is transferred to the imaging lens 103
An image is formed on the image sensor 104 or the like. Here, by scanning the mirror unit 102 equipped with mirrors M2 and M3 at 1/2 the scanning speed of the lamp unit 101 equipped with the light source LA and mirror M1, the distance from the document surface to the imaging lens is The optical path length is always kept constant.

In the figure, reference numeral 110 denotes a pulley for driving the lamp unit and mirror unit, and a drive source 11
1 power is transmitted to each unit via wires 113 and 114. The reason why two wires are used to support both ends of each unit is to ensure running stability of each unit.

0004

[Problems to be Solved by the Invention] The image reading device having the above-mentioned configuration is provided with a part that fixes the scanning unit so that it does not move in the traveling direction in order to prevent damage during transportation. This is set at the factory and shipped. The fixing method is required to be easy for the user to operate, and to not cause damage to each part even if subjected to impact such as dropping.

FIG. 6 shows an example of a conventionally used fixing method during transportation. FIG. 6(a) is a plan view, and FIG. 6(b) is a side view. Reference numeral 116 denotes a fixing lever attached to the main body of the apparatus, which has two fixed positions for locking and unlocking with respect to the main body of the apparatus. The figure shows the locked state. The shaft portion 116a at the tip of the fixing lever passes through the main body, and in the locked state, the shaft portion 116a at the tip of the fixing lever is inserted into the fixing hole 1 of the drive pulley 110.
15 and disables rotation of the drive pulley. This fixes the lamp unit and mirror unit to the main body.

By the way, in consideration of variations in the dimensional accuracy of parts and variations in assembly adjustment, the fixing hole 11 of the drive pulley is
5 has a long shape in the direction of rotation. Therefore, in the event of an impact such as a fall, the drive pulley rotates by the amount of play in the fixing hole relative to the fixing shaft. On the other hand, a pulse motor is often used as a drive source, but a holding torque acts on the pulse motor even when the power source is not connected, and it acts as a brake against the rotation of the drive pulley.

The difference between the impact force and the braking force is applied to the meshing portion of the gear, but if the strength of the gear cannot withstand this difference, phenomena such as scratches on the teeth, breakage of the teeth, or tooth skipping occur. As a result, the device may stop working,
This may cause problems such as distorted images.

[0008]

[Means for Solving the Problems] The present invention provides an image reading device in which a fixing member is placed on the drive transmission means of the exposure scanning means during transportation, and the exposure scanning means is made inoperable during transportation. By disengaging the transmission of the drive transmission means, making the exposure scanning means operable during use, and connecting the drive transmission means at the same time, the drive transmission means is prevented from being damaged by a drop impact during transportation.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the illustrated embodiments. FIG. 3 shows a schematic configuration of an image reading device according to the present invention. FIG. 3(a) is a plan view, and FIG. 3(b) is a side view. In the figure, reference numeral 1 denotes an image sensor such as a CCD as a reading means, and is arranged inside the base frame 4. On the other hand, a document placing glass 3 is provided above the main body 2 of the apparatus, and an exposure scanning means scans the placed document P to form an image on the image sensor 1 .

The exposure scanning means includes a wire-driven lamp unit 5 and a mirror unit 6, and is mounted on the base frame 4 together with the lens 7 and the image sensor 1. The lamp unit 5 includes an illumination lamp L that illuminates the document P, and a first lamp that reflects the image reflected light from the document surface irradiated by the illumination lamp L toward the mirror unit 6 side.
It is equipped with a mirror M1. On the other hand, the mirror unit is provided with second and third mirrors M2 and M3 that return the image light reflected by the first mirror M1 toward the image sensor.

Lamp unit 5 and mirror unit 6
is supported by a shaft 8a and a rail 8b on the base frame 4 so as to be able to scan parallel to the optical axis while maintaining a right angle to the optical axis of the lens 7.

Reference numeral 9 denotes a pulse motor which is a driving source for scanning the exposure scanning means, and its rotation is controlled by a drive pulley 1 through a gear train.
0. Generally, in this type of image reading device, a pulse motor is often used as a drive source because position control and speed control are easy. Two wires 1 are connected to the drive pulley 10 at one point along the way.
1a and 11b are wound. Each wire is fixed to the lamp unit in the middle, and is passed half way around the pulleys 12a and 12b at both ends of the mirror unit to the base frame 4.
One end of it is fixed to. Also, the other end of the wire is attached to pulley 1
2a and 12b half way around the tension spring 1.
They are combined at 3. As a result, the mirror unit scans at half the speed of the lamp unit based on the principle of a movable pulley, so the optical path length is always kept constant over the entire scanning area.

The exposure scanning means is normally set at a home position near the original reading start position by a home position sensor (not shown). When receiving a read start command from the host, a motor drive pulse synchronized with the image sensor's read synchronization signal is given to the motor, the motor rotates, the exposure scanning system starts scanning, and the read image data is sent to the host. .

FIGS. 1 and 2 are diagrams illustrating a method of fixing an exposure scanning means according to the present invention during transportation. Figure 1
2, (a) is a plan view, and (b) is a side view. FIG. 1 shows the operating state in which the lock is released and the drive transmission system is connected, and FIG. 2 shows the state during transportation in which the exposure scanning means is locked and the drive transmission system is disconnected. In the figure, 10 is a drive pulley, 17 is a gear that meshes with the gear part 10a of the drive pulley,
Transmits the rotation of the motor to the drive pulley. A substrate 14 rotatably supports the drive transmission system from the drive pulley to the motor, and at the same time has a claw portion 14a for fixing the exposure scanning means, and is rotatably supported around the shaft of the motor. 15 is a spring that urges the substrate 14, and 16 is a lever for switching between fixing and releasing the exposure scanning means.

In a normal operable state, the substrate 14 is in the posture shown in FIG. 1, that is, with the drive transmission system connected, the spring 15 biases the gears 10a and 17 in the direction of engagement, and the device is operable.

[0016] After completing one reading, the exposure scanning means always returns to the home position (usually near the reading start edge of the original).
Return to At this time, the drive pulley stops when the notch 10b reaches the position shown in FIG. In other words, when turning off the power, be sure to close the notch 10 of the drive pulley.
b is in the position shown in the same figure. Here, when the switching lever 16 is rotated clockwise, the gear 17 is rotated clockwise and the connection with the gear 10a is released.At the same time, the claw portion 1 of the board 14
4a is fitted into the notch 10b of the drive pulley and is biased by the spring 15 in the direction of biting into it, making the drive pulley unrotatable and fixing the exposure scanning system as well.

In the conventional example, a set of meshing teeth between the gear of the drive pulley and the gear of the preceding stage could be damaged by receiving the full impact load in a very small area of line contact. On the other hand, in this method, when the exposure scanning system is fixed, the drive transmission system is disconnected, so there is no risk of gear teeth being damaged. Also, since it will hold down the outer circumference of the drive pulley,
The impact force applied to the fixed lever is reduced compared to the conventional method. This greatly improves the impact resistance of the device. Furthermore, in this method, the substrate of the drive transmission system also has the function of fixing the exposure scanning system, so there is almost no increase in cost compared to the conventional example.

In the explanation of this embodiment, a 1:1/2 optical system is used as an exposure scanning system and a wire is used as a drive transmission means, but the invention is not limited to this, and mirrors, lenses, and image sensors can be used as an example. The present invention can also be applied to an integrated exposure scanning system built into a unit or a device using a belt-based drive transmission system.

Furthermore, although the present embodiment has been described with respect to an image reading device that exposes a line image sensor, the present invention is not limited to this, and can also be applied to a copying machine or the like that exposes a photoreceptor.

Embodiment 2 FIG. 4 shows a second embodiment of the present invention. FIG. 4(a) is a plan view, and FIG. 4(b) is a side view. In the figure, the same parts as those in the previous embodiment are denoted by the same numbers.

The difference between this embodiment and Embodiment 1 is that the motor, drive transmission system, and parts fixed during transportation are separated from the base frame 4 on which the exposure scanning system is mounted, and the bottom frame 4 on which the power supply and control board are mounted is separated. This is because it is placed on the cover. When the base frame 4 incorporating the exposure scanning system is placed on the bottom cover 20 incorporating the electrical components, the drive pulley 10 on the base frame 4 enters between the drive transmission system of the board 14 and the claw portion 14a. As in the previous embodiment, switching between the state in which the drive system is connected and the state in which the exposure scanning means is fixed is performed by rotating the switching lever 16.

This embodiment has the following advantages compared to the above embodiments. First, by separating the motor from the base frame, vibrations of the motor are less likely to be transmitted to the exposure scanning system, so it is expected that the quality of the read image will improve. Second, since the base frame is lighter, it becomes more resistant to impacts from drops and vibrations. Third, by placing the motor in a unit on which other electrical components are mounted, cables can be easily connected, improving assembly work efficiency.

[0023]

[Effects of the Invention] As explained above, by adopting the present invention, the impact load caused by falling during transportation, which conventionally was applied to one tooth of the drive transmission system, can be completely removed, and the impact resistance has been improved. can be improved. It should be noted that, compared to the conventional example, there is almost no increase in cost due to the adoption of the present invention.

Furthermore, image quality and assembly workability are improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram when the lock is released in a first embodiment of the present invention.

FIG. 2 is an explanatory diagram when locked in the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an image reading device to which the present invention is applied.

FIG. 4 is a diagram for explaining a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a conventional image reading device.

FIG. 6 is a diagram for explaining a locking mechanism of a conventional image reading device.

[Explanation of symbols]

5 Lamp unit 6 Mirror unit 9 Pulse motor 10 Drive pulley 14 Drive transmission system mounting board 16 Fixed/release switching lever

Claims (4)

[Claims] 1. A scanning means for moving and scanning a document, a first drive transmission means for applying a driving force to the scanning means, and a first drive transmission means for transmitting a driving force from a drive source to the first drive transmission means. In an image reading device that reads image light from a document scanned by the scanning means, the second drive transmission means is movable, and the second drive transmission means is movable. Due to the movement, the first drive transmission means and the second drive transmission means can take a first mode in which they are connected and the driving force is transmitted, and a second mode in which they are separated and the driving force is cut off. An image reading device characterized in that the first drive transmission means is made inoperable in the second mode. 2. The image reading device according to claim 1, wherein means for disabling said first drive transmission means is provided on said second drive transmission means. 3. The image reading device according to claim 1, wherein the second drive transmission means rotates between the two modes around the axis of a drive source of the device. 4. The image reading apparatus according to claim 2, wherein the second drive transmission means and the drive source of the apparatus are provided outside the unit in which the scanning means is mounted.