A number of monochrome pages printed by a print system in a color mode and a total number of pages printed by the print system are monitored. A ratio of the number of monochrome pages printed by the print system in the color mode to the total number of pages printed by the print system is determined. The print system is switched between the color mode and a monochrome mode of the print system mode based on the ratio so as to reduce color cartridge wear of the print system and/or so as to reduce transitions between the color mode and the monochrome mode while printing monochrome pages.

An image forming unit forms test images of a color of the same type as a first color using toner of a second color and toner of a third color, transfers first and second test images, fixes the test images on a sheet, controls a sensor to read the test images, determines sampling timings for the test images based on an output signal related to the first test image outputted from the sensor using a color filter of a fourth color, acquires a result of reading the test images based on a reading result of the test images on the sheet by the color sensor using a color filter of the first color and the sampling timing, and determines a transfer voltage based on the result of reading the test images.

In an image forming apparatus, an image forming unit configured to form a toner image on a transfer medium includes four sets of a photoconductor drum and a development roller, respectively, for forming toner images of first, second, third and fourth colors, arranged in this order, in a direction opposite to a direction of movement of the transfer medium moving toward a detector configured to detect a toner image formed on the transfer medium. A controller executes a bias-corrective test image forming process in which a first bias-corrective test image of the first color is arranged in a position downstream of other three first bias-corrective test images, and a second bias-corrective test image of the first color is arranged in a position between two first bias-corrective test images selected among other three first bias-corrective test images, in the direction of movement of the transfer medium.

A developing cartridge includes: a casing; a developing roller; a shaft; and a cam. The casing is configured to accommodate developer therein. The developing roller is rotatable about a first axis extending in an axial direction. The shaft extends along a second axis extending in the axial direction. The shaft is movable along the second axis. The cam is movable along the second axis in response to axial movement of the shaft. The cam has a cam surface non-parallel with the second axis.

A method of converting a CMYK Standard Color Printer to print with a white toner such that a CMYW Converted White Printer is created. The CMYK Standard Color Printer may be an Oki® printer, such as C821dn, C822n, C823dn, C830n, C830dn, C831DM, C831n, C831dn, C833dn, C841dn, C843dn, or C844dnw.

In an image forming apparatus, a controller performs processes in accordance with an operation mode settable to one of a first subscription mode and a second subscription mode. The first subscription mode corresponds to a first subscription in which a specific-color cartridge is a subscription subject and a non-specific-color cartridge is not the subscription subject. The second subscription mode corresponds to a second subscription in which both the specific-color cartridge and the non-specific-color cartridge are the subscription subject. The controller performs restricting usage of the non-specific-color cartridge in a case where the first subscription mode is set as the operation mode and the type information of the non-specific-color cartridge indicates the subscription type, compared to a case where the second subscription mode is set as the operation mode and the type information of the non-specific-color cartridge indicates the subscription type.

A white toner for electrostatic image development contains white toner particles that contain a binder resin and a white pigment and satisfy condition 1 below: condition 1: a grain size distribution index GSD.sub.vL of the white toner particles satisfies formula (1) below, and a ratio of a number of white toner particles having a diameter of 3 μm or less to a total number of white toner particles is 1% by number or more and less than 6% by number:
1.2≤GSD.sub.vL(=D.sub.84v/D.sub.50v)≤1.5  formula (1):
(in formula (1), D.sub.84v is a particle diameter at which a cumulative frequency cumulated from a small diameter side in a volume-based particle size distribution is 84%, and D.sub.50v is a particle diameter at which the cumulative frequency cumulated from the small diameter side in the volume-based particle size distribution is 50%).

An image processing apparatus includes a processor configured to: store a first color patch used in using metallic toner and a second color patch used in using CMYK toner other than the metallic toner without using the metallic toner; receive a first colorimetric value obtained by measuring color of the first color patch and a second colorimetric value obtained by measuring color of the second color patch; calculate a third colorimetric value on a basis of the first colorimetric value obtained by measuring the color of the first color patch and the second colorimetric value obtained by measuring the color of the second color patch, and generate a profile to be used to convert an input color value into an output color value, the profile being generated on a basis of the third colorimetric value; and calculate the third colorimetric value that ranges from the first colorimetric value to the second colorimetric value in response to a total amount of CMYK toner being lower than or equal to a threshold, the total amount of the CMYK toner resulting from color conversion of the input color value performed by using the profile, and calculate the third colorimetric value that coincides with the first colorimetric value in response to the total amount exceeding the threshold.

A liquid electro-photographic printing system, comprising: a binary ink developer assembly, a power supply arrangement, a switching arrangement, and a controller. The binary ink developer assembly includes a plurality of members defining a flow path for a printing fluid containing charged particles, the plurality of members including a first member and a second member that are arranged to generate an electric field therebetween, the first member having a plurality of segments. The power supply arrangement continuously provides a supply of voltages during a print operation, the voltages including a first voltage and a second voltage having a different voltage level from that of the first voltage. The switching arrangement switches the supply of voltages to the segments of the first member on an individual segment basis, to cause charged particles to be attracted to the first member in the individual segment when the first voltage is supplied to the individual segment and to cause charged particles to be repelled from the first member in the individual segment when the second voltage is supplied to the individual segment. The controller to determine timing of when to switch the supply of voltages to the segments.

An image forming apparatus includes an image forming device, a detector and a holding body. The image forming device is configured to perform an image formation to a sheet. The detector is configured to detect a position of a first image formed on a first surface of the sheet through the image formation of the image forming device. The holding body is configured to move while holding the sheet, by performing one of a rotation in a radial direction about a support shaft attached thereto in a direction perpendicular to an axial direction thereof and a lateral shift in a width direction of the sheet, operable to correct the position of the sheet based on a detection result obtained by the detector.