Document transport device and image forming apparatus

Abstract

A document transport device includes a transport unit that transports documents one by one to a position where an image is read by an image reading unit and transports the document at a speed at which the image reading unit can read the image at the image reading position, and a controller that determines, based on an instruction from an image forming apparatus to which the document transport device is mounted, the number of sheets transported per unit time when plural documents are transported by the transport unit, and controls the transport unit to transport the documents at the determined number of sheets transported per unit time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in detail based on the following figures, wherein:

FIG. 1 is a sectional view showing a structure of an image forming apparatus;

FIG. 2 is a block diagram showing a functional structure of the image forming apparatus;

FIG. 3 is an enlarged view of a main part of an ADF of FIG. 1;

FIG. 4 is a view showing a relationship between the time since the transport of a document was started in the ADF and the transport speed;

FIG. 5 is a view showing a relationship between the time since the transport of a document was started in the ADF and the transport speed;

FIGS. 6A to 6D are views showing a situation in which the leading edge of a document goes into a nip part of a transport roller; and

FIG. 7 is a view showing a relationship between the time since the transport of a document was started in the ADF and the transport speed;

Claims

1. A document transport device comprising: a transport unit that transports documents one by one to a position where an image is read by an image reading unit and transports the document at a speed at which the image reading unit can read the image at the image reading position; anda controller that determines, based on an instruction from an image forming apparatus to which the document transport device is mounted, the number of sheets transported per unit time when a plurality of documents are transported by the transport unit, and controls the transport unit to transport the documents at the determined number of sheets transported per unit time.

2. A document transport device comprising: a transport unit that transports documents one by one to a position where an image is read by an image reading unit and transports the document at a speed at which the image reading unit can read the image at the image reading position; anda controller that determines, based on an instruction from an image forming apparatus to which the document transport device is mounted, a transport pattern of the document transported by the transport unit and the number of sheets transported per unit time, and controls the transport unit to transport the documents at the determined number of sheets transported per unit time and in the determined transport pattern.

3. The document transport device according to claim 2, wherein the transport pattern includes at least one of a transport speed of a document, a timing of transport start and stop of the document, an acceleration at a time when the transport speed of the document is accelerated to a specified speed, and a timing of start and stop of the acceleration.

4. The document transport device according to claim 3, wherein the transport speed of the document by the transport unit, the timing of the transport start and stop of the document, the acceleration at the time when the transport speed of the document is accelerated to the specified speed, or the timing of the start and stop of the acceleration is indicated by a control parameter, and when the controller determines the transport speed of the document, the timing of the transport start and stop of the document, the acceleration at the time when the transport speed of the document is accelerated to the specified speed, or the timing of the start and stop of the acceleration, the controller controls the transport unit based on the control parameter indicating the determined content.

5. The document transport device according to claim 2, wherein the instruction from the image forming apparatus includes the number of sheets transported per unit time and mode information to indicate at least one of an operation mode to reduce noise and an operation mode to reduce electric power consumption, and the controller determines the transport pattern that the number of sheets transported per unit time included in the instruction is transported in the operation mode indicated by the mode information included in the instruction from the image forming apparatus.

6. The document transport device according to claim 5, wherein the controller determines an acceleration method in which an acceleration at a time when the transport speed of the document is accelerated to a specified speed is made low or acceleration is performed stepwise when the mode information included in the instruction from the image forming apparatus indicates the operation mode to reduce the noise.

7. The document transport device according to claim 5, wherein the controller prolongs a time from a timing of transport start of the document to a timing of stop when the mode information included in the instruction from the image forming apparatus indicates the operation mode to reduce the electric power consumption.

8. An image forming apparatus comprising: the document transport device;a controller to give the instruction to the document transport device; andan image forming unit to form an image read from a document transported by the document transport device onto a record sheet,the document transport device comprising:a transport unit that transports documents one by one to a position where an image is read by an image reading unit and transports the document at a speed at which the image reading unit can read the image at the image reading position; anda controller that determines, based on an instruction from an image forming apparatus to which the document transport device is mounted, the number of sheets transported per unit time when a plurality of documents are transported by the transport unit, and controls the transport unit to transport the documents at the determined number of sheets transported per unit time.

9. An image forming apparatus comprising: a document transport device including a transport unit that transports documents one by one to a position where an image is read by an image reading unit and transports the document at a speed at which the image reading unit can read the image at the image reading position, and a controller that controls the transport unit to transport the documents at the number of sheets transported per unit time by the transport unit based on an instruction from an image forming apparatus mounted with the document transport device; anda controller that determines the number of sheets transported per unit time when the document transport device transports a plurality of documents, and gives the instruction to the document transport device.

10. The document transport device according to claim 1, wherein the speed at which the document passes through the reading unit is constant.

11. The image forming apparatus according to claim 8, wherein the speed at which the document passes through the reading unit is constant.

12. The image forming apparatus according to claim 9, wherein the speed at which the document passes through the reading unit is constant.