Mita Industrial Co., Ltd.

Sadao Tanigawa

Yoshiki Shimomura

Tetsuo Tomiyama

Yasushi Umeda

Hiroyuki Yoshikawa

Kazuhiro Ogawa

Yukihiro Mori

Kenji Katsuhara

Kazuto Hori

Toshimitsu Takakura

Tomohiko Sakao

Hirofumi Nishino

Yuichi Koike

A sheet transportation device for use in an image forming apparatus is provided which has self-diagnosis and self-repair functions. The sheet transportation device has a sheet transportation system including a plurality of units (8). A control sequence for a sheet transportation operation is applied from a system body (10) to the respective units (8). The units (8) each execute the control sequence to perform the sheet transportation operation. The units (8) are each constructed so as to perform an autonomous operation. This construction allows the respective units to autonomously perform self-diagnosis and repair operations. The fault diagnosis and repair operations are performed in parallel to the sheet transportation control. Therefore, the sheet transportation device can flexibly adapt itself to an external influence such as a change in the use environment and a malfunction due to a time-related change such as the aging of components thereof. Thus, the sheet transportation device ensures a highly reliable operation and yet requires less labor for the maintenance and inspection.

Sheet transportation device

A simulation system is provided which is capable of simulating the behavior of a sheet transported by a transportation system. In response to application of a control sequence formulated for the sheet transportation system, a simulation is performed to check how the sheet is to be transported in the sheet transportation system on the basis of the applied control sequence. Necessary data are extracted from hardware systems constituting the real sheet transportation system. On the basis of the extracted data, a virtual sheet transportation system is constructed in a computer, and the sheet is represented by information indicative of the locations of opposite ends of the sheet and the distance therebetween. The sheet thus represented is moved by a predetermined unit distance in the virtual sheet transportation system on the basis of the control sequence, and data is computed for every movement of the sheet.

Simulation system for control sequence for sheet transportation

The present invention makes it possible to make good self-repair on which little secondary effect is exerted by calculating a manipulated variable of a parameter at the time of the repair by a functional amount in an image forming apparatus having a self-repair function. When a fault occurs, control-type repair for operating a physical parameter is first made. In this repair, the physical parameter to be operated is searched for (n3). If the physical parameter to be operated is determined, a manipulated variable of the physical parameter is then calculated by a functional amount (n4). The manipulated variable of the parameter by the functional amount is determined by adjusting the degree to which a plurality of functions are developed. Therefore, a manipulated variable in which the development of the functions is most preferable as the entire apparatus is determined. If the fault cannot be repaired by the control type repair, functional redundancy type repair is made (n6, n7, n8, n9). In the functional redundancy type repair, priorities to repair candidates are determined by the functional amount.

Self-reparir type image forming apparatus utilizing functional

According to the present invention, a concept of functional quantities indicative of quantified functional degrees of such lower-level functions as 'clearer characters', 'cleaner background', and 'thicker characters', which are subordinating to a qualification-oriented function of 'more beautiful characters'. Characteristic patterns of functional quantities F1, F2 and F3 of the lower-level functions for physical parameters (for example, the surface potential of a photoreceptor body) are prepared. When a fault repair is implemented by changing a value of a physical parameter, a tradeoff occurs between lower-level functions which are influenced by the physical parameter. That is, taking into account the functional quantities F1, F2 and F3 of the lower-level functions, the value of the physical parameter is set so that the functional quantity of the function of 'more beautiful characters' is maximized. By introducing the concept of the functional quantities indicative of the quantified functional degrees of the functions, a flexible self-repairing function can be realized, thereby optimizing a repair operation.

Apparatus having self-repairing function and method of self repairing

A method of automatically creating control sequence software required for a machine system controlled by a computer includes four algorithms, that is, 'derivation of control sequence specification'.fwdarw.'derivation of a qualitative control sequence'.fwdarw.'addition of quantitative information (derivation of a quantitative control sequence)'.fwdarw.'generation of a C program'. The qualitative control sequence is a state transition matrix following the time sequence. This qualitative control sequence is derived by making use of a qualitative inference system. A quantitative control sequence is obtained by adding quantitative time between states to the qualitative control sequence. Time information is calculated on the basis of design information of a machine portion stored in a design information database. As a result, it is possible to reduce the manual burden on the software development by using the present invention.

Method of automatically creating control sequence software and apparatus

An image forming apparatus capable of detecting a toner image density well by shifting a developing bias. In adjusting a fog density or a solid density, the developing bias is shifted by a specified width so as to form an image of a gray density. This enables detection of the fog density and the solid density to be replaced with detection of a density in a gray density region where a reflection type photosensor can detect a density with high sensitivity. Thus, densities in a fog or solid density region where usually an output from the reflection type photosensor is saturated can be detected with high accuracy.

Image forming apparatus including improved toner image density detecting

In an image forming apparatus according to the present invention, a software portion incorporated in the apparatus is provided with a virtual case storage portion 12, to previously create virtual cases by a virtual case compiler 16 outside of the apparatus and store the virtual cases. Fault diagnosis is made by comparing fuzzy qualitative values into which the values of sensors are converted on the basis of fuzzy membership functions with the virtual cases. If a fault is diagnosed as a result of the comparison, repair operations for repairing the fault are read out from a work script table 15. In this case, operation information for repair are stored to correspond to each of a plurality of domains into which a state space which the apparatus can take up is divided. Accordingly, it is possible to correctly read out corresponding repair operations from the work script table 15 depending on which of the domains is a domain to which the present state of the apparatus belongs. As a result, a self-repair system can be constructed as a practical built-in type system, thereby to make it possible to reduce the scale of the system related to the fault diagnosis as well as to reduce time required for the fault repair.

Image forming apparatus having self-repair function and self-repair

An image forming apparatus has a functional redundancy system by which an inherent function normally performed by a certain portion is performed as a potential function by another portion, when such certain portion no longer can be perform its inherent function. In a first operative sequence, portions in the image forming apparatus perform their respective inherent functions. However, where a function of a certain portion in the apparatus is lost, for example, where a fault occurs and a particular element has failed, operation of other portions in the apparatus are controlled according to a second sequence. In the second sequence, the inherent function of the portion which has failed is replaced by the potential function of another portion in the apparatus.

Image forming apparatus having functional redundancy system

According to the present invention, a self-diagnosis system for an image forming apparatus can make accurate fault diagnosis and is made smaller in size and higher in speed. For that purpose, a fault temporarily developed by the image forming apparatus is limited to a single fault assumption, all states which can exist on the image forming apparatus when the image forming apparatus develops the fault are previously simulated, and the results of the qualitative simulation are stored as a plurality of virtual cases in a virtual case storing portion 12. When the image forming apparatus is operated, detected values of sensors X, Vs and Ds are converted into fuzzy qualitative values, respectively, on the basis of membership functions stored in a membership function generating portion 13. The fuzzy qualitative values are compared with the virtual cases stored in the virtual case storing portion 12, to reason the cause of the fault. Accordingly, any of the virtual cases stored in the virtual case storing portion 12 is selected using the fuzzy qualitative values, thereby to make it possible to accurately specify the fault in a short time.

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Osaka, Japan

Sadao Tanigawa