Canon Kabushiki Kaisha

Shoji Takeda

Satoru Yamamoto

Keita Takahashi

Hirotaka Seki

Atsushi Otani

Akihiko Sakai

Shigeo Hata

Akihiro Shimizu

Wataru Kawata

Masahiko Yokota

Hideaki Kosasa

Ryuichi Kojima

Toshiro Tomono

Akinobu Nishikata

Hiroshi Tanioka

Hidenori Sunada

Katsuyuki Yamazaki

Nobuo Sekiguchi

Yoshihito Osari

Tadaaki Saida

Yuichiro Maeda

An image forming apparatus includes a photosensitive member, a light source, a deflecting unit, a storing unit, a correcting unit, and a light source driving portion. Magnification correction data is determined using a quadratic function of a variable representing a scanning position with respect to a scanning direction. Coefficients of two quadratic functions corresponding to adjacent two regions included in a plurality of scanning regions are set so that a differential value calculated at the variable corresponding to a boundary of the two regions by a differential of the quadratic function for one region and a differential value calculated at the variable corresponding to the boundary of the two regions by a differential of the quadratic function for the other region are equal to each other.

Image forming apparatus

An image processing apparatus includes (A) a dither processing unit to perform dither processing on first image data to generate second image data, the second image data including a target pixel and an adjacent pixel, each of the pixels having a density value, the density value of the target pixel being greater than that of the adjacent pixel, and the density value of the adjacent pixel being not greater than a predetermined density, (B) a diffusing unit (a) to determine an error value resulting at the target pixel, (b) to diffuse the error value to pixels subsequent to the target pixel, and not to diffuse an error value resulting at the adjacent pixel to pixels subsequent to the adjacent pixel.

Image processing apparatus, method, and storage medium, that perform dither processing on first image data to generate second image data having pixels of varying density

A pulse generation unit is configured to output pulse signals for driving the stepping motor. A control unit is configured to perform acceleration control or deceleration control of the stepping motor via the pulse generation unit. The control unit is configured to calculate a number of the pulse signals to be output from the pulse generation unit to the stepping motor when accelerating or decelerating the stepping motor at constant acceleration in the acceleration control or the deceleration control based on an initial speed of the stepping motor when the acceleration control or the deceleration control starts, a target rotation speed, and time from start control of the stepping motor to time when the stepping motor reaches the target rotation speed, and change a rotation speed of the stepping motor in the acceleration control or the deceleration control along a sinusoidal waveform.

Motor control device and image forming apparatus

Separately providing a shift register for performing serial-to-parallel conversion on a BD signal and a shift register for performing parallel-to-serial conversion on a bit pattern to generate a PWM signal increases the scale of a circuit for adjusting a writing start position in the scanning direction of a light beam. Therefore, the shift register for performing serial-to-parallel conversion on a BD signal and the shift register for performing parallel-to-serial conversion on a bit pattern to generate a PWM signal are configured as a common register.

Data processing apparatus and image forming apparatus having shift register for parallel and serial signal conversions

A setting unit of a controller mounted on a control board sets a first mode for generating, from image data, PWM data indicating a pattern for causing an LD to emit light and transmitting to a laser driving board, or a second mode for transmitting to the laser driving board image data prior to generation of the PWM data. A data conversion unit, in the first mode, converts inputted image data into N pieces of PWM data respectively corresponding to N LDs, and in the second mode, converts inputted image data into image data for each scanning line. A P/S conversion unit converts data outputted from the data conversion unit from a serial format into a parallel format, and transmits the converted data to the laser driving board as control data.

Controller

A PWM signal generating apparatus configured to generate a PWM signal by applying parallel serial conversion to pattern data obtained by converting input data into a waveform pattern of a PWM signal having one pulse divided into a predetermined number of pulses, the PWM signal generating apparatus including: a clock generating circuit configured to generate a plurality of clock signals having mutually different phases; a conversion circuit configured to convert the input data into the waveform pattern of the PWM signal; an encoding circuit configured to generate, from the waveform pattern, a plurality of encoded signals synchronized with respective clocks of the plurality of clock signals generated by the clock generating circuit; and a decoding circuit configured to generate the PWM signal from the plurality of encoded signals output from the encoding circuit.

PWM signal generating apparatus, motor control apparatus, and light scanning apparatus

The present image forming apparatus includes a first control unit and a second control unit driven by built-in clock oscillators to realize the distributed control. The first control unit generates, using a first timer driven by the built-in clock oscillator of the first control unit, a pulse signal corresponding to a predetermined clock rate and outputs the pulse signal to the second control unit. The second control unit measures, using a second timer driven by the built-in clock oscillator of the second control unit, a pulse width of the pulse signal outputted from the first control unit, and calculates a correction coefficient using reference pulse width corresponding to the predetermined clock rate and the measured pulse width. The processing unit processes using the calculated correction coefficient.

Image forming apparatus and control apparatus

This invention provides an image forming apparatus to which a distributed control system is applied and which improves error detection accuracy in each control unit. To accomplish this, the image forming apparatus includes a master control unit which controls the overall image forming apparatus, a plurality of sub-master control units which control a plurality of functions required to implement image formation, and a plurality of slave control units which control loads required to implement the plurality of functions. Each slave control unit includes a monitoring unit which monitors the operation of the other active slave control unit and performs an error diagnosis when the slave control unit is inactive.

This invention provides an image forming apparatus that suppresses a control error between CPUs when the CPUs operate in cooperation with each other in distributed control by the CPUs. To accomplish this, the image forming apparatus utilizes a distributed control system. Respective CPUs measure time interval concerning image formation processing using their built-in clock oscillators, and perform operations in cooperation with each other. Correction coefficients are calculated based on the time interval measured by the respective CPUs to correct a measurement error generated by the operation an error of the respective clock oscillators. Clock count values each indicating a timing to drive a load is corrected based on the correction coefficients.

The image forming apparatus has the plurality of control units and executes distributed processing in which any one control unit having monitoring execution authority monitors for an abnormal condition in each control unit. Each control unit determines, from its own processing load, monitoring capability information that indicates whether monitoring for an abnormal condition is possible or not. If, in a case where the control unit has the monitoring execution authority, the monitoring capability information does not satisfy predetermined information, then the control unit delegates the monitoring execution authority to another control unit whose monitoring capability information does satisfy the predetermined information.

There are provided an image forming apparatus which implements divisional control using a plurality of control units without an increase in cost and a control method for the apparatus. To accomplish this, this image forming apparatus includes a master control unit that controls the overall image forming apparatus, a plurality of sub-master control units that control a plurality of functions for performing image formation, and a plurality of salve control units that control loads for implementing a plurality of functions. The master control unit is connected to the plurality of sub-master control units via first signal lines. The plurality of sub-master control units are connected to the plurality of slave control units via second signal lines higher in data transfer timing accuracy than the first signal lines.

Image forming apparatus implemented by a distributed control system

An engraving processing apparatus includes a laser engraving unit configured to perform engraving processing for forming a recessed portion on a sheet by irradiating a laser beam onto the sheet, and a controller configured to control an engraving processing operation of the laser engraving unit.

Engraving processing apparatus and image forming apparatus

There is provided an image forming apparatus which adopts a distributed control system and suppresses generation of radiation noise without increasing the cost. To accomplish this, the image forming apparatus includes a master control unit that controls the overall image forming apparatus, a plurality of sub-master control units that control a plurality of functions for performing image formation, and a plurality of salve control units that control loads for implementing a plurality of functions. The image forming apparatus performs distributed control. The image forming apparatus determines the operating frequencies of the salve control units in accordance with loads controlled by the salve control units. The image forming apparatus compares the operating frequencies of the slave control units. Based on the comparison result, the image forming apparatus changes the operating frequency of a slave control unit that is equal to the operating frequency of another slave control unit.

Provided is an image forming apparatus that realizes a distributed control system with a reduced number of power lines, and that has highly reliable power supply and an effective power saving mode. To accomplish this, the image forming apparatus employs a distributed control system including a master CPU, a plurality of sub master CPUs, and a plurality of slave CPUs. The master CPU supplies 5-V power to the sub master CPUs and the slave CPUs in the power saving mode, and supplies 24-V power thereto in a normal mode. Also, the sub master CPUs determine the operating mode in accordance with the level of the supplied power voltage, and operate accordingly.

Image forming apparatus that forms an electrostatic latent image on a surface of a photosensitive member with a laser beam, including a generation unit configured to generate a high-speed clock and a low-speed clock mutually different in frequency, a scanning unit configured to perform scanning of the laser beam in a main scanning direction based on the low-speed clock, a detection unit configured to detect the laser beam during a scanning operation performed by the scanning unit, a first shift register unit configured to receive a detection signal from the detection unit according to the high-speed clock, and an output unit configured to receive a parallel output of the first shift register unit in synchronization with the low-speed clock and to output detection timing of the laser beam as a detection signal synchronized with the low-speed clock and a value corresponding to a shift number defined by the high-speed clock.

Growing community of inventors

Tokyo, Japan

Shoji Takeda