Photosensitive material processing apparatus and photosensitive material processing method using the same

A photosensitive material processing apparatus including a conveyance roller pair disposed near an insertion opening, which nips the leading end of a photosensitive material and transports the photosensitive material at a predetermined conveyance speed (VR) when the photosensitive material is inserted until it is nipped by the conveyance roller pair, the photosensitive material processing apparatus comprising:

• a plurality of sensors for detecting the photosensitive material, the sensors being disposed in the upstream of the conveyance roller pair along the width direction of the photosensitive material, being able to detect photosensitive materials having different sizes in the width direction thereof, and being divided into at least two groups that are offset from each other in the conveyance direction of the photosensitive material;
• means for storing in advance an offset distance (LOS) between a first sensor group and a second sensor group adjacent thereto in the conveyance direction, and a conveyance direction (LIN) between a reference sensor group as one of the sensor groups and the position at which the conveyance roller pair nips the photosensitive material;
• means for computing an insertion speed (VH) of the photosensitive material from a detecting time difference (Δt) between the detecting time of the first sensor group and the detecting time of the second sensor group, and an offset distance (LOS) between the first and second sensor groups, and then computing an insertion time required for the photosensitive material to be conveyed at the insertion speed (VH) by the conveyance distance (LIN);
• means for computing the length (L) of the photosensitive material in the conveyance direction thereof by multiplying the time, that is obtained by subtracting the insertion time (LIN/VH) from the detecting time (X) during which the photosensitive material has been detected by the reference sensor group, by the conveyance speed of the conveyance roller pair (VR) and then adding thereto the conveyance distance (LIN);
• means for determining the length (W) of the photosensitive material in the width direction thereof based on the detection results of the plurality of sensors;
• and
• means for computing the process area (S) of the photosensitive material from the computed length (L) of the photosensitive material in the conveyance direction thereof and the determined length (W) of the photosensitive material in the width direction thereof.

A photosensitive material processing method, comprising the steps of:

• (a) disposing a conveyance roller pair, which nips the leading end of a photosensitive material and rotates, near an insertion opening;
• (b) disposing a plurality of sensors for detecting the photosensitive material in the upstream of the conveyance roller pair along the width direction of the photosensitive material, and offsetting at least two groups of sensors from each other in the conveyance direction of the photosensitive material;
• (c) inserting a photosensitive material until it is nipped by the conveyance roller pair;
• (d) obtaining a detecting time (X) during which a reference sensor group has detected the photosensitive material;
• (e) reading out an offset distance (LOS) in the conveyance direction between a first sensor group and a second sensor group adjacent thereto;
• (f) reading out a detecting time difference (Δt) that is the time difference between the time when the first sensor group detects the photosensitive material and the time when the second sensor group detects the photosensitive material;
• (g) computing an insertion speed VH from the offset distance (LOS) and the detecting time difference (Δt);
• (h) reading out an insertion distance (LIN) between the reference sensor group and the position at which the conveyance roller pair nips the photosensitive material, and a conveyance speed (VR) of the conveyance roller pair, the insertion distance being the distance between the reference sensor group and the conveyance roller pair;
• (i) computing the length (L) of the photosensitive material in the conveyance direction thereof using the equation (1) below:
• L=(X−LIN/VH)×VR+LIN (1)
• wherein L:
• the length of the photosensitive material in the conveyance direction thereof;
• VR:
• the conveyance speed;
• LIN:
• the insertion distance;
• VH:
• the insertion speed;
• and X:
• detecting time (X) during which the reference sensor group is detecting the photosensitive material;
• (j) determining the length (W) of the photosensitive material in the width direction thereof based on the detection results of the sensors;
• (k) computing a process area (S) of the photosensitive material from the length (L) of the photosensitive material in the conveyance direction thereof computed in step (i) and the length (W) of the photosensitive material in the width direction thereof determined in step (j);
• and
• (l) computing an appropriate amount of replenisher based on the computed process area (S).