In a general aspect, a method for authenticating a plurality of slave devices connected to a master device can include: generating and sending by the master device a respective challenge to each slave device; in each slave device, generating a response to the respective challenge and transmitting it to the master device; verifying by the master device the response of one of the slave devices; returning by the master device the remaining responses to respective slave devices distinct from those that generated the responses; and verifying by each slave device the response returned thereto by the master device and transmitting the result of the verification to the master device.

An image forming apparatus which is capable of reducing a load on a data bus therein when controlling an image reading apparatus depending on its image processing capability. When acquired identification information about the image forming apparatus is included in a clock control table 600, a clock frequency for controlling hardware of the image reading apparatus in accordance with the clock control table 600, while setting the clock frequency therefor to a default setting of the clock control table 600 when the acquired identification information is not included in the clock control table 600, wherein a minimum value of clock frequencies in the clock control table 600 is set as the default setting of the clock control table 600.

An image processing device includes a plurality of image processors cascaded into a plurality of stages, the image processors each performing image processing on image data received, wherein an image processor other than an image processor in the final stage performs image processing on image data being part of image data input, and transfers the remaining image data to an image processor in a subsequent stage.

An image forming apparatus which is capable of reducing a load on a data bus therein when controlling an image reading apparatus depending on its image processing capability. When acquired identification information about the image forming apparatus is included in a clock control table 600, a clock frequency for controlling hardware of the image reading apparatus in accordance with the clock control table 600, while setting the clock frequency therefor to a default setting of the clock control table 600 when the acquired identification information is not included in the clock control table 600, wherein a minimum value of clock frequencies in the clock control table 600 is set as the default setting of the clock control table 600.

According to an embodiment of the present invention, to improve processing performance, a printing apparatus that performs printing by using a printhead formed by a plurality of headchips includes one CPU, a table configured to store processing contents set by the CPU, and a plurality of processing units configured to process, in parallel, printing data to be used in each headchip by commonly using the table and in accordance with the processing contents set in the table. In addition, the apparatus includes a plurality of control units configured to wait for the completion of the processing of each processing unit, synchronize the plurality of processing units for next processing, and cause each of the processing units to execute the next processing in accordance with the processing contents set in the table.

An image processing apparatus receives print data via a USB interface, receives print data via a network interface, processes an HTTP protocol, receives print data via the USB interface, and controls a printer to perform print processing. When the first print data is not based on IPP, the first print data is transmitted to a print processing module, and when the second print data is based on IPP via a network interface, the second print data is transmitted to a Web server module. When the third print data is based on IPP via the USB interface, the third print data is transmitted to a TCP/IP processing module and transmitted to a Web server module, and when the Web server module receives the second or third print data from the TCP/IP processing module, it transmits the second or third print data to the print processing module.

Example embodiments of the present disclosure include image processing apparatus installed with a web browser that includes circuitry and an image processing device. The circuitry interprets content obtained from a web server connected to the image processing apparatus via a network, displays a screen based on the interpreted content, requests the web server to process according to a user input on the displayed screen, and requests the image processing device to perform predetermined image processing.

A transmitting and receiving system includes a first information processing apparatus and a second information processing apparatus. The first information processing apparatus includes a first cache memory, and the second information processing apparatus includes a second cache memory. The second information processing apparatus is configured to transmit and receive information to and from the first information processing apparatus. When transmission information to be transmitted from the first information processing apparatus to the second information processing apparatus is stored in the first cache memory of the first information processing apparatus, the first information processing apparatus transmits partial information that is included in the stored transmission information to the second information processing apparatus or transmits identification information that identifies the transmission information to the second information processing apparatus.

Provided is an image processing apparatus to form an image on a sheet of paper, including a main body and a submodule detachably disposed on the main body. The main body includes an asynchronous serial bus and a master control unit. The submodule includes a slave control unit. An interactive asynchronous serial communication is performed between the master control unit and slave control unit. The master control unit includes a detection timing changing unit. The detection timing changing unit changes a scheduled timing to detect a second signal. The slave control unit includes a transmission signal changing unit. The transmission signal changing unit changes a state of the second signal from a first state detectable by the master control unit at a first timing to a second state detectable by the master control unit at a second timing.

An image forming apparatus includes a memory that stores a program, and a processor that executes the program. When a USB control module receives PDL data from a second host computer via a USB interface, the PDL data is transmitted to a print processing module, and when a TCP/IP processing module receives first IPP print data from a first host computer, the first IPP print data is transmitted to a Web server module. When the USB control module receives second IPP print data from the second host computer, the second IPP print data is transmitted to the TCP/IP processing module by loopback and the second IPP print data is transmitted to the Web server module, and when the Web server module receives the first or second IPP print data from the TCP/IP processing module, the first or second IPP print data is transmitted to the print processing module.