The control portion 90 at least includes a CPU (central processing unit) 91 as a central arithmetic processor, a ROM (read-only memory) 92 as a read-only storage portion, a RAM (random-access memory) 93 as a readable and rewritable storage portion, a temporary storage portion 94 that temporarily stores image data and the like, and a plurality of (here, two) I/Fs (interfaces) 95 that transmit control signals to different blocks in the color printer 100 and receive input signals from an operation portion 80.

The ROM 92 stores a control program for the color printer 100 as well as data that are not changed during the use of the color printer 100, such as values necessary for control. The RAM 93 stores necessary data generated in controlling the color printer 100, data temporarily required in controlling the color printer 100, and the like. The temporary storage portion 94 temporarily stores the image signal input from the image input portion 70 and converts it into a digital signal.

The control portion 90 transmits control signals from the CPU 91 via the I/Fs 95 to different parts and blocks in the color printer 100. From those parts and blocks, signals indicating their states and input signals are transmitted via the I/Fs 95 to the CPU 91. Examples of the parts and blocks controlled by the control portion 90 include the image forming portions Pa to Pd, the exposure device 5, the fixing portion 13, the image input portion 70, and the operation portion 80.

The control portion 90 can use information about the toner containers 4a to 4d that is acquired by the odor sensor 50 and stored in the RAM 93 to control the color printer 100. For example, by outputting the information stored in the RAM 93 to the liquid crystal display portion 81 and referring to it on the occasion of a failure or the like of the color printer 100, it is possible to expedite the identification of the cause of the failure.

When the toner containers 4a to 4d are identified as genuine or non-genuine products, the control portion 90 changes the image forming conditions according to the identified toner containers 4a to 4d as necessary. For example, if the toner containers 4a to 4d are non-genuine products and the image density is lower than the target value, the control portion 90 changes the image forming conditions as by increasing the development voltage.

FIG. 7 is a diagram showing, as a modified example of the color printer 100 of the first embodiment, a configuration in which one odor sensor 50 moves to sense the odor generators 40 on the toner containers 4a to 4d. The toner containers 4a to 4d are similar in configuration to those shown in FIGS. 2 to 4.

In the configuration in FIG. 7, the odor sensor 50 can move among positions (measurement positions) facing the odor generators 40 on the toner containers 4a to 4d. When sensing the odor substance, the odor sensor 50 is stopped at one after another of the measurement positions to sense the odor substances from the odor generators 40 on the toner containers 4a to 4d.

When not sensing the odor substance, the odor sensor 50 is kept on standby at a position (home position HP) not facing any of the odor generators 40. This makes it difficult for the molecules of the odor substance diffused from the odor generator 40 to reach the odor sensor 50. As a result, the odor sensor 50 can be kept in surroundings low in odor substances, so it is possible to prevent adhesion of odor substances to the odor sensor 50 and to prevent deterioration of the odor sensor 50, thereby extending the life of the odor sensor 50.

When sensing proceeds with the odor sensor 50 moving from one to the next of the odor generators 40 on the toner containers 4a to 4d, it is preferable to move to the open position only the shutter 41 (see FIG. 3) of that one of the toner containers 4a to 4d from which the odor substance is to be sensed, and to arrange the shutters 41 of the other toner containers 4a to 4d in the closed position. This prevents the diffusion of the odor substances from the odor generators 40 from which the odor substances are not to be sensed, thereby enhancing the sensing accuracy of the odor sensor 50 for odor substances.

In the case of a sensitive membrane type odor sensor 50, when it is exposed to dry air after the molecules of the odor substance have adsorbed on the sensitive membrane, the molecules desorb from the sensitive membrane and the sensor 50 returns to its original state. Each time sensing is complete for one odor generator 40, the odor sensor 50 can be moved to the home position HP to be exposed to dry air so that the odor sensor 50 is reset. It is thus possible to continuously and accurately sense the odor substances from the plurality of the odor generators 40. It is also possible to prevent deterioration of the odor sensor 50, leading to an extended life of the odor sensor 50.

When sensing proceeds with the odor sensor 50 moving from one to the next of the odor generators 40 on the toner containers 4a to 4d, the partition walls 51a forming the odor retention portion 51 (see FIG. 4) are formed of an elastic material, a flexible sheet material (urethane seal), or the like. This prevents the odor sensor 50 from being scratched or damaged due to contact with the partition walls 51a.

FIG. 8 is a plan view, as seen from above, of another example of the toner containers 4a to 4d in the color printer 100 of the first embodiment, showing a configuration in which the toner containers 4a to 4d each include two odor generators 40.

Arranging two odor generators 40 on each of the toner containers 4a to 4d permits measurement of two types of odor substances. For example, by using different odor substances in the two odor generators 40, it is possible, with one odor generator 40, to sense whether the toner containers 4a to 4d are genuine or non-genuine products and, with the other odor generator 40, to acquire information such as the color of the toner and the manufacturing date of the toner. Here, two odor generators 40 are provided, but it is also possible to arrange three or more odor generators 40. A plurality of odor sensors 50 may be arranged at positions corresponding to the different odor generators 40, or one odor sensor 50 may be moved so as to sense them.

[3. Identifying Rotary Toner Container by Use of Odor Sensor]

FIG. 9 is a side sectional view of toner containers 4a to 4d and a toner supplying path used in a color printer 100 according to a second embodiment of the present disclosure. FIG. 10 is a side view of the toner containers 4a to 4d used in the color printer 100 according to the second embodiment, and shows an example in which an odor generator 40 is arranged on a fixing portion 43. The toner containers 4a to 4d all have basically a similar structure, so the toner containers 4a to 4d are represented by one of them in FIG. 10, and also in FIG. 11, which will be referred to later. In this embodiment, rotary toner containers 4a to 4d are used; that is, the toner containers 4a to 4d themselves rotate to supply toner.

As shown in FIG. 9, the toner containers 4a to 4d are connected to the development devices 3a to 3d via a toner supplying pipe (sub hopper) 35. The toner supplying pipe 35 is bent in a crank shape. Inside a horizontal part of the toner supplying pipe 35, a conveyance screw 35a is arranged and the toner conveyance screw 35a is coupled to a conveyance motor 35b.

As shown in FIG. 10, the toner containers 4a to 4d each have a container body 42 and a fixing portion 43. The container body 42 is configured to be rotatable about a rotation axis extending in the longitudinal direction. The container body 42 stores toner of each color (not shown). On the inner circumferential surface of the container body 42, a conveyance rib 42a in a spiral shape is continuously provided. The conveyance rib 42a projects inward in the radial direction from the inner circumferential surface of the container body 42.

The fixing portion 43 is mounted on, so as not to be rotatable relative to, a mounting portion 101a (see FIG. 9) in the container mounting portion 101. In the fixing portion 43, a toner discharging port 43a is formed to be coupled to the toner supplying pipe 35. On the top face of the fixing portion 43, the odor generator 40 is arranged.

Referring back to FIG. 9, near the mounting portion 101a, a toner supplying motor 33 is arranged to rotate the container body 42. As the toner supplying motor 33 rotates the container body 42, the toner inside the container body 42 moves toward the fixing portion 43 by the action of the conveyance rib 42a, and then the toner falls from the toner discharging port 43a into the toner supplying pipe 35. The toner that has fallen into the toner supplying pipe 35 is supplied to the development devices 3a to 3d as the conveyance screw 35a rotates.

Arranging the odor generator 40 on the fixed portion 43 of the toner containers 4a to 4d prevents the odor generator 40 from rotating together with the container body 42, and this permits the odor sensor 50 to be fixed and arranged at a position facing the odor generator 40.

As shown in FIG. 11, the odor generator 40 can be arranged at the center of a bottom surface 42b of the container body 42. In this case, the position of the odor generator 40 does not change even if the container body 42 rotates, and this too, as in FIG. 10, permits the odor sensor 50 to be fixed and arranged at a position facing the odor generator 40.

In the configurations of FIGS. 10 and 11, by aligning the orientation of the odor generators 40 on the toner containers 4a to 4d, it is possible, as shown in FIG. 7, to move one odor sensor 50 from one to the next of the positions facing the odor generators 40 to sense the odor substances.

When not sensing the odor substance, as shown in FIG. 7, the odor sensor 50 is kept on standby at a position (home position HP) not facing any of the odor generators 40. As a result, the odor sensor 50 can be kept in surroundings low in odor substances, so it is possible to prevent deterioration of the odor sensor 50, thereby extending the life of the odor sensor 50.

The timing to sense the odor substance with the odor sensor 50 can be when the toner containers 4a to 4d are replaced. The replacement of the toner containers 4a to 4d can be sensed by use of an open/closed signal with respect to a container cover 102, as shown in FIG. 12, that opens and closes the container mounting portion 101 when the toner containers 4a to 4d are inserted or removed. The container cover 102 is provided so as to be openable and closable at the rear of the color printer 100 and the container mounting portion 101 is fitted with, at a position at which it makes contact with the container cover 102, an open/closed sensing switch 103. When the container cover 102 is opened and closed, an open/closed signal is transmitted from the open/closed sensing switch 103 to the control portion 90 (see FIG. 6).

However, when the power to the color printer 100 is off, whether the container cover 102 is open or closed cannot be recognized. To cope with that, assuming that the toner containers 4a to 4d may have been inserted with the power off, the odor substance may be sensed when the power to the color printer 100 is turned on. If the container cover 102 can be locked except when the toner containers 4a to 4d need to be replaced, there is no need to sense the odor substance when the power is turned on.

Instead, the replacement of the toner containers 4a to 4d may be checked by the user. The odor sensing operation after reception of an open/closed signal with respect to the container cover 102 or at the power-on of the color printer 100 may be limited to after occurrence of an empty signal for the toner containers 4a to 4d. If a plurality of toner containers 4a to 4d have been newly mounted, sensing may be performed with the replaced toner containers 4a to 4d rotated simultaneously; or to prevent the influence of the odor generators 40 on the other toner containers 4a to 4d, the odor substance may be sensed with the replaced toner containers 4a to 4d rotated one by one. Table 1 shows an example of situations in which to sense the odor substance and the toner containers targeted for sensing.