JPH10107946A - Transmission mechanism for scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prescribed resolution by allowing two drive gears of two kinds of step motors the mesh with two transmission gears fitted to a frame so as to select either of the two kinds of the stepping motors of different types without changing the transmission structure. SOLUTION: A stepping motor 20 is fixed to a fixing hole 14 so that a drive gear 22 fitted to its drive shaft is placed to a main shaft hole 12. On the other hand, a 1st transmission gear 24 is made up of a large gear 241 and a small gear 242 configured concentrically, the large gear 241 meshes with the drive gear 20 and the small gear 242 meshes with an intermediate gear 30. The Number of teeth of the drive gear 22 is 14N (N is a natural number), the number of teeth of the the large gear 241 of the 1st transmission gear 24 is 45N and the number of teeth of the small gear 242 is 17N, and the number of teeth of the intermediate tear 30 is 25N. Then the intermediate gear 30 meshes with respective large gears 321 of two 2nd transmission gears 32 at the same time. A large gear 321 and a small gear 322 of each 2nd transmission gear 32 mesh respectively with a follower gear 34 driving a paper feed roller, Thus, the two different step motors are selected and a prescribed resolution is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission mechanism for a scanner, and more particularly to a transmission mechanism for a scanner which can be applied to two types of stepping motors having different rotation speeds by combining one frame with a transmission gear set. .

[0002]

2. Description of the Related Art Conventionally, there are various types of desk scanners, and the most significant difference among them is the arrangement of a transmission mechanism. Resolution 30
With respect to ODPI scanners, those skilled in the art will most often choose a PM or HYBRID type stepper motor to select a suitable transmission mechanism for the two different rotational speeds, thereby reducing speed and reducing paper. The feed rotor is rotating. Among the two types of step motors, the step angle of one step of the PM type is 7.
5 °, and the step angle of one step of the HYBRID type is 1.8 °. Therefore, a different transmission mechanism is used for each step motor, and each step motor needs to be mounted on a different frame. In addition, it is a factor that increases costs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a transmission mechanism for a scanner which can be applied to two types of step motors having different rotation speeds in accordance with a single type of frame and a transmission gear set. For that purpose.

Another object of the present invention is to reduce the required rotational speed simply by replacing a drive gear attached to the drive shaft of a step motor with a first transmission gear between the drive gear and the transmission mechanism. It is an object of the present invention to provide a scanner transmission mechanism that can be obtained.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a transmission mechanism for a scanner applicable to two types of scanners, which has a mounting frame on which any of two types of step motors can be assembled. The drive gear assembled to the drive shaft of the above operates a transmission mechanism composed of a replaceable first transmission gear assembled to the frame and two replaceable gears, and the two second transmission gears are The intermediate gear meshes with the large gears of the two second transmission gears, and the small gear of each second transmission gear set is A paper feed roller is provided coaxially with the following gear.

[0006]

Preferred embodiments of the present invention will be described below. This embodiment is an example of a transmission mechanism applied to a desktop scanner having a resolution of 300 DPI.

FIG. 1 is a plan view of the structure of a scanner frame which is a part of the transmission mechanism of the scanner according to the present invention. The frame 10 of the scanner is provided with a spindle hole 12 and a fixing hole 14 for mounting a step motor, a pivot hole 16 for assembling a transmission mechanism, and a pivot groove 18 for attaching a paper feed roller. ing. A plurality of the fixing holes 14 are provided, and any of the two types of step motors can be attached. Also, the pivot holes 16 are provided at two places, and are used for pivotal connection of two types of first transmission gears 24,
The frame 10 can be shared by two types of step motors.

FIG. 2 shows that the frame 10 shown in FIG.
FIG. 2 is an exploded layout view showing an attachment relationship between an M type step motor 20 and a transmission mechanism related thereto. As shown in FIG. 2, the stepping motor 20 is fixed to the fixing hole 14 so that the driving gear 22 assembled to the driving shaft is located in the main shaft hole 12. On the other hand, the first transmission gear 24 is a coaxial large gear
241 and a small gear 242.
Meshes with the drive gear 22, and the small gear 242 meshes with the intermediate gear 30. The number of gears of the drive gear 22 is 14N (N = natural number), the number of teeth of the large gear 241 of the first transmission gear 24 is 45N, the number of teeth of the small gear 242 is 17N, and the number of teeth of the intermediate gear 30 is 25N.

The intermediate gear 30 simultaneously meshes with the respective large gears 321 of the two second transmission gears 32. The large gear 321 and the small gear 322 of the second transmission gear 32 mesh with a follower gear 34 that drives a paper feed roller (not shown). The number of teeth of the large gear 321 of the second transmission gear 32 is 34 N
The number of teeth of the small gear 322 is 25N, and the following gear 34
Has 42N teeth.

By connecting the drive gear 22 of the PM type step motor 20 to the first transmission gear 24 and the transmission mechanism formed on the frame 10, the following final transmission amount (mm / ste) is obtained.
p) can be obtained. (7.5 ゜ x π / 180 ゜) x (14/45) x (17/25) x (25/3
4) × (25/42) × φ = 0.01212φ (radian / step) In the case of φ = 14 mm, the distance the paper advances by driving the step motor 20 by one step is 0.01212 × 14
= 0.16968 mm / step. Therefore, a resolution of 0.08484 mm / half step can be obtained by driving the step motor 20 by half step.

FIG. 3 shows that the frame 10 shown in FIG.
FIG. 8 is a layout diagram showing an attachment relationship between an RID type step motor 20 ′ and a transmission mechanism related thereto. As shown in FIG. 3, the stepping motor 20 'is fixed to the fixing hole 14 such that the driving gear 22' assembled to the driving shaft is located in the main shaft hole 12. On the other hand, the first transmission gear 24 ′ is interposed between the drive gear 22 ′ and the first gear 321 of the second transmission gear 32. The number of teeth of the driving gear 22 'is 22N, and the number of teeth of the first transmission gear 24' is 25N. The intermediate gear 30, the second transmission gear 32 and the follower gear 34 used here are all the same as those shown in FIG.

The HYBRID type step motor
By coupling the 20 'drive gear 22' to the first transmission gear 24 'and the transmission mechanism formed on the frame 10, the following final transmission amount (mm / step) can be obtained. (1.8 ゜ × π / 180 ゜) × (22/25) × (25/34) × (25/4
2) × φ = 0.01212φ (radian / step) In the case of φ = 14 mm, the forward distance by driving the step motor 20 by one step is 0.01210 × 14 = 0.694.
0 mm / step. Therefore, a resolution of 0.08470 mm / half step can be obtained by driving the step motor 20 by half step.

In general, the final transmission amount of a step motor used for a 300 DPI scanner is 0.08450 to 0.084.
Preferably, it is 850 mm / half step.

[0014]

As can be seen from the above description, the two types of step motors 20 and 20 'are constructed by connecting their drive gears 22 and 22' to the first transmission gears 24 and 24 'mounted on the frame 10. By choosing different types of step motors 20, 20 'without changing the structure of the transmission mechanism, a given resolution can be obtained. As described above, according to the scanner transmission mechanism of the present invention, only one type of frame 10, each of the same intermediate gear 30, two second transmission gears 32, and two following gears 34 are employed, and two types of frames 10 are used. Since the present invention can be applied to a step motor, the cost of the scanner can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a frame structure of a scanner which is a part of a transmission mechanism for a scanner according to the present invention.

FIG. 2 is a layout diagram showing an attachment relationship between a PM type step motor and a transmission mechanism relating to the step motor on the frame shown in FIG. 1;

FIG. 3 is a layout diagram showing an attachment relationship between a HYBRID type step motor and a transmission mechanism relating to the HYBRID type step motor on the frame shown in FIG. 1;

[Explanation of symbols]

 10 ... Frame 12 ... Spindle hole 14 ... Fixed hole 16 ... Pivot hole 18 ... Pivot groove 20, 20 '... Step motor 22, 22' ... Driving gear 24 , 24 '... first transmission gear 241 ... large gear 242 ... small gear 30 ... intermediate gear 32 ... second transmission gear 321 ... large gear 322 ... small gear 34 ..Follow-up gears

Claims (3)

[Claims] 1. A transmission mechanism for a scanner applied to two types of scanners, comprising a mounting frame to which any of two types of step motors can be mounted, and a drive mounted to a drive shaft of each of the step motors. The gear meshes with a replaceable first transmission gear mounted on the frame, and the first transmission gear engages with the intermediate gear,
While operating a transmission mechanism composed of two second transmission gears and two following gears, the two second transmission gears are each composed of a coaxial large gear and a small gear,
Also, the intermediate gear meshes with the large gears of the two second transmission gears, and the small gears of each second transmission gear set mesh with all of the following gears and are coaxial with each of the following gears. A transmission mechanism for a scanner, wherein a paper feed roller is provided. 2. A step angle of one of the two step motors is 7.5 °, and the first transmission gear is
2. The transmission mechanism for a scanner according to claim 1, comprising a coaxial large gear and a small gear, wherein said large gear meshes with a drive gear of said step motor, and said small gear meshes with an intermediate gear. 3. A step angle of one of the two step motors is 1.8 °, and the first transmission gear is
2. The transmission mechanism for a scanner according to claim 1, wherein the transmission gear meshes with a drive gear of the step motor and meshes with a large gear of one second transmission gear.