Printing apparatus

• US 20090184466A1
• Filed: 01/21/2009
• Published: 07/23/2009
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: RISO Kagaku Corporation
• Original Assignee: RISO Kagaku Corporation
• Inventors: MAEDA, Yukihiro, HARA, Masashi
• Granted Patent: US 8,141,872 B2
• Time in Patent Office: Days
• US Class Current: 271/314
• CPC Class Codes: B65H 2220/01 indicating an entity as a function of which control, adjustment or change is performed, i.e. input
• CPC Class Codes: B65H 2220/02 indicating an entity which is controlled, adjusted or changed by a control process, i.e. output
• CPC Class Codes: B65H 2220/09 indicating that several of an entity are present
• CPC Class Codes: B65H 2404/14 Roller pairs
• CPC Class Codes: B65H 2511/514 Particular portion of element
• CPC Class Codes: B65H 2513/10 Speed
• CPC Class Codes: B65H 2801/06 Office-type machines, e.g. photocopiers
• CPC Class Codes: B65H 29/125 between two sets of rollers

Abstract

A printing apparatus comprises: a first paper discharge roller unit 411 and a second paper discharge roller unit 412 which are configured to transport a print sheet to a discharge port; a upper transportation roller unit 401 configured to transport the print sheet to the first paper discharge roller unit 411; a drive control unit 302 configured to determine a transportation speed; an upper side paper discharge drive unit 270 configured to drive both the paper discharge roller units at the determined transportation speed after starting transportation of the print sheet until the print sheet leaves the upper transportation roller unit 401, and drive both the paper discharge roller units at a discharge speed which is determined independently from the transportation speed until the print sheet leaves the second paper discharge roller unit 412.

Claims

1. A printing apparatus comprising:

a paper discharge roller unit configured to transport a print sheet to a discharge port;

a transportation roller unit configured to transport the print sheet to the paper discharge roller unit;

a transportation speed determination unit configured to determine a transportation speed at which the transportation roller unit is driven; and

a paper discharge roller drive unit configured to drive the paper discharge roller unit at the transportation speed determined by the transportation speed determination unit during the time that the print sheet is being transported by the transportation roller unit, and then drive the paper discharge roller unit at a discharge speed which is determined independently from the transportation speed after the print sheet has left the transportation roller unit while the print sheet is being transported by the paper discharge roller.

2. The printing apparatus as claimed in claim 1 wherein

there are provided, as the paper discharge roller unit, a first paper discharge roller unit located near the transportation roller unit and a second paper discharge roller unit located near the discharge port, wherein

a print sheet sensor is provided between the first paper discharge roller unit and the second paper discharge roller unit, and wherein

the paper discharge roller drive unit detects when the print sheet leaves the transportation roller unit on the basis of the detection result by the print sheet sensor, the distance between the sensing position of the print sheet sensor and the transportation roller unit, the length of the print sheet in the transportation direction, and the transportation speed determined by the transportation speed determination unit.

3. The printing apparatus as claimed in claim 2 wherein

the paper discharge roller drive unit detects when the print sheet leaves the paper discharge roller unit on the basis of the detection result by the print sheet sensor, the distance between the sensing position of the print sheet sensor and the second paper discharge roller unit, and the discharge speed.

4. The printing apparatus as claimed in claim 2 wherein

there is a space between the transportation roller unit and the first paper discharge roller for allowing the print sheet, which is being transported, to warp in the space.

5. The printing apparatus as claimed in claim 1 wherein

a print sheet sensor is provided between the discharge roller unit and the discharge port, and wherein

the paper discharge roller drive unit detects when the print sheet leaves the transportation roller unit on the basis of the detection result by the print sheet sensor, the distance between the transportation roller unit and the sensing position of the print sheet sensor, the length of the print sheet in the transportation direction, and the transportation speed determined by the transportation speed determination unit.

6. The printing apparatus as claimed in claim 5 wherein

the paper discharge roller drive unit detects when the print sheet leaves the paper discharge roller unit on the basis of the detection result by the print sheet sensor.

7. The printing apparatus as claimed in claim 1 wherein

a circulating transportation route is provided for causing the print sheet to circulate in the housing of the printing apparatus, and wherein

the transportation speed determination unit determines the transportation speed to be equivalent to the discharge speed in the case where the print sheet is not circulated around the circulating transportation route.

8. The printing apparatus as claimed in claim 1 wherein

a print transportation drive unit is provided for transporting the print sheet on which ink is sprayed, and wherein

the transportation speed is determined to be higher than the speed of the print sheet which is transported by the print transportation drive unit during spraying ink on the print sheet.

9. The printing apparatus as claimed in claim 8 wherein

the speed of transporting the print sheet during spraying ink on the print sheet is determined on the basis of a printer option which is selected by the user, and wherein

the transportation speed is determined in accordance with a print schedule which is determined in advance of printing with respect to the order of print tasks and the interval between adjacent print tasks.