Electrophotography – Image formation – Exposure
Reexamination Certificate
2001-07-31
2003-05-13
Braun, Fred L. (Department: 2852)
Electrophotography
Image formation
Exposure
C358S474000, C399S211000
Reexamination Certificate
active
06564028
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and a computer program product for initializing a scanner to be used in an image processing apparatus, such as a multifunctional DPPC (i.e., Digital Plain Paper Copier), and more particularly to a method and a computer program product that can control the movement of the carriage of the scanner for performing the initializing process of the scanner in a short period of time.
2. Discussion of the Background
The recently developed DPPC may be configured such that power is supplied to the whole system of the DPPC by turning on the power switch. Further, the DPPC may be put in the shutdown state by stopping the power supply using a power key (e.g., a soft key), except some power may still be supplied to a monitoring part. In these types of DPPC's, when the power switch is turned on or when a return operation from the shutdown state is performed, an initializing process of the scanner is performed. In the initializing process of the scanner, an automatic adjustment to the reading function of the scanner is made after the homing operation of the scanner is completed. An image reading device carried by the carriage reads a white plate arranged above the track of the carriage. The read image is then converted into an electric signal by an image sensor (i.e., generally, a CCD linear image sensor is used).
The automatic adjustment to the reading performance of the scanner is made based on the output electric signal. The output electric signal generated by reading the white plate includes various distortions caused by variations in the reading optical system, the lighting system, and the image sensor, etc. Therefore, shading data, for performing a correction in the analog signal process and the analog/digital conversion process, which are performed in the signal processing system of the image sensor, is acquired based on the detected value of the distortions. The automatic adjustment to the reading performance of the scanner is made based on the acquired shading data for correcting the variation in the sensitivity of the sensor (i.e., CCD sensor) and the uneven distribution of light of the lighting system.
In the scanner, the movement of the carriage which carries the reading device is controlled according to respective conditions when the initializing process is performed or when an image reading operation of the original document is performed. As illustrated in
FIG. 14
, the carriage is controlled to move in the forward or in the reverse directions within the home position sensor active (effective) range, the white plate active (effective) range, and the original document reading range. The three ranges are provided in order along the track of the carriage. In the home position sensor active (effective) range, the output of the home position sensor (i.e., HPS) to detect the position of the carriage is active (effective). In the white plate active (effective) range, the white plate is arranged and the white plate reading signal is active (effective).
In the initializing process of the scanner, the homing operation, which is performed based on the output of the HPS, and the reading operation of the white plate are performed. The white plate is provided between the HPS active (effective) range and the original document reading range.
The initializing process is described below referring to the flowchart in
FIG. 15
, which illustrates initializing process steps of the scanner when the power switch is turned on or when the return operation from the shutdown state is performed.
According to the steps, the carriage firstly moves in a forward direction for a predetermined distance to reach a position where the output of the HPS is apparently inactive (ineffective) at step S
71
. That is, the carriage moves toward the white plate or the original document side until it reaches the position where the output of the HPS is inactive (ineffective) after passing through the range where the output of the HPS is active (effective) wherever the carriage is positioned. Then, whether or not the output of the HPS is inactive (ineffective) is checked at step S
72
.
When it is determined that the output of the HPS is inactive (ineffective), whether or not the output of the HPS switches (changes) to be active (effective) from being inactive (ineffective) is checked at step S
77
while moving the carriage in a minimal amount in a reverse direction at step S
74
. When it is determined that the output of the HPS switches (changes) to be active (effective), the position of the scanner is detected as the original position (i.e., a fiducial position) for the scanning operation at step S
78
(i.e., a homing operation). When the output of the HPS does not switch (change) to be inactive (ineffective) even if the carriage is moved by the predetermined distance at step S
72
(i.e., No at step S
72
) or when the output of the HPS does not switch (change) to be active (effective) even if the carriage is moved in the reverse direction within the allowable range at step
74
(i.e., No at step S
75
), it is determined that the scanner malfunctions. Error processes, for example, to stop the operation, are performed at steps S
73
and S
76
.
The carriage then moves in the forward direction for a predetermined distance at step S
79
from the detected original position to reach a position where the white plate is read. An automatic adjustment to the reading performance of the scanner is made at step S
80
based on the read value of the white plate. When the adjustment is made, the carriage moves for a predetermined distance in the reverse direction to a standby position (i.e., original position) at step S
81
. The scanner is put into the standby state at step S
82
. The process is then finished.
The initializing process operation performed according to the above-described processing steps is further explained referring to timing diagrams in
FIGS. 16 through 18
which show the mutual relationship between the position of the carriage and the output of the HPS.
The timing diagrams in
FIGS. 16 through 18
illustrate that the carriage is located in a different position at power-on time. In
FIG. 16
, the position of the carriage is shifted to the side of the white plate with respect to the switching (changing) point of the output of the HPS. In
FIG. 17
, the carriage is positioned close to the switching (changing) point of the output of the HPS. In
FIG. 18
, the position of the carriage is shifted to the side of the physical restrictive position with respect to the switching (changing) point of the output of the HPS. According to these examples of the present invention, a sensor having a hysteresis property in which the switching (changing) point of the output differs according to the moving direction is used as the HPS to detect active (effective) and inactive (ineffective) positions. The original position of the carriage is then detected when the output of the sensor switches (changes) to be active (effective) from being inactive (ineffective) while the carriage moves in the reverse direction.
In any of these examples shown in
FIGS. 16 through 18
, the homing operation is started after the carriage moves in the forward direction for a predetermined distance to reach the position where the output of the HPS is apparently inactive (ineffective). That is, the original position of the scanner for the scanning operation is detected when the output of the HPS switches (changes) to be active (effective) from being inactive (ineffective) while the carriage moves in the reverse direction. Therefore, the example shown in
FIG. 16
(i.e., when the position of the carriage is shifted to the side of the white plate with respect to the switching (changing) point of the output of the HPS) requires the longest poriod of time for detecting the original position of the scanner among the examples shown in
FIGS. 16 through 18
. The same operation is performed in any of the examples shown in
FIGS. 16 through 18
until the scanner is put in the
Braun Fred L.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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